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Full vulnerability report · 2026
CVE-2026-53209High confidence

Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend

Linux · Linux

7.8HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

20 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivelinuxAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-awsAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azureAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azure-fdeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-azure-nvidiaAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gcpAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gkeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gkeopAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-ibmAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-lowlatencyAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-nvidiaAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-nvidia-lowlatencyAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-nvidia-tegraAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oem-6.11Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oracleAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspiAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-riscvAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-xilinxAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-53209 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitykernel: Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend
108 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • bpftool as a component of Red Hat Enterprise Linux 9
  • kernel as a component of Red Hat Enterprise Linux 9
  • kernel-64k as a component of Red Hat Enterprise Linux 9
  • kernel-64k-core as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-core as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-devel as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-devel-matched as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-modules as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-modules-core as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-modules-extra as a component of Red Hat Enterprise Linux 9
  • kernel-64k-debug-modules-internal as a component of Red Hat Enterprise Linux 9
Summary
A flaw was found in the Bluetooth subsystem of the Linux kernel, specifically within the `hci_sync` component. This vulnerability occurs when the `hci_adv_bcast_annoucement()` function attempts to prepend Broadcast Announcement service data to an existing advertising payload that is already at its maximum size. This can lead to an oversized data packet that may overrun a temporary buffer, potentially causing a denial of service (DoS) or other unpredictable system behavior.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-39300

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend Existing advertising instances can already hold the maximum extended advertising payload. When hci_adv_bcast_annoucement() prepends the Broadcast Announcement service data to that payload, the combined data may no longer fit in the temporary buffer used to rebuild the advertising data. Reject that case before copying the existing payload and report the failure through the device log. This keeps the existing advertising data intact and avoids overrunning the temporary buffer.

What

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend Existing advertising instances can already hold the maximum extended advertising payload. When hci_adv_bcast_annoucement() prepends the Broadcast Announcement service data to that payload, the combined data may no longer fit in the temporary buffer used to rebuild the advertising data. Reject that case before copying the existing payload and report the failure through the device log. This keeps the existing advertising data intact and avoids overrunning the temporary buffer.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend Existing advertising instances can already hold the maximum extended advertising payload. When hci_adv_bcast_annoucement() prepends the Broadcast Announcement service data to that payload, the combined data may no longer fit in the temporary buffer used to rebuild the advertising data. Reject that case before copying the existing payload and report the failure through the device log. This keeps the existing advertising data intact and avoids overrunning the temporary buffer.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Out-of-bounds Write → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-787 ↗

CWE-787: Out-of-bounds Write. The product writes data past the end, or before the beginning, of the intended buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-787
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2026-2077Linux Kernel: Mehrere Schwachstellen

Ein entfernter Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um Sicherheitsvorkehrungen zu umgehen, einen Denial-of-Service-Zustand herbeizuführen und weitere, nicht näher spezifizierte Auswirkungen zu erzielen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260701Security Bulletin 1 July 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 1 July 2026, published on 1 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1162Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2026-53200 Référence CVE CVE-2026-53201 https://www.cve.org/CVERecord?id=CVE-2026-53201 Référence CVE CVE-2026-53202 https://www.cve.org/CVERecord?id=CVE-2026-53202 Référence CVE CVE-2026-53203 https://www.cve.org/CVERecord?id=CVE-2026-53203 Référence CVE CVE-2026-53204 https://www.cve.org/CVERecord?id=CVE-2026-53204 Référence CVE CVE-2026-53205 https://www.cve.org/CVERecord?id=CVE-2026-53205 Référence CVE CVE-2026-53206 https://www.cve.org/CVERecord?id=CVE-2026-53206 Référence CVE CVE-2026-53207 https://www.cve.org/CVERecord?id=CVE-2026-53207 Référence CVE CVE-2026-53208 https://www.cve.org/CVERecord?id=CVE-2026-53208 Référence CVE CVE-2026-53209 https://www.cve.org/CVERecord?id=CVE-2026-53209 Référence CVE CVE-2026-53210 https://www.cve.org/CVERecord?id=CVE-2026-53210 Référence CVE CVE-2026-53211 https://www.cve.org/CVERecord?id=CVE-2026-53211 Référence CVE CVE-2026-53212 https://www.cve.org/CVERecord?id=CVE-2026-53212 Référence CVE CVE-2026-53213 https://www.cve.org/CVERecord?id=CVE-2026-53213 Référence CVE CVE-2026-53214 https://www.cve.org/CVERecord?id=CVE-2026-53214 Référence CVE CVE-2026-53215 https://www.cve.org/CVERecord?id=CVE-2026-53215 Référence CVE CVE-2026-53216 https://www.cve.org/CVERecord?id=CVE-2026-53216 Référence CVE CVE-2026-53217 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1064Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2026-53192 Référence CVE CVE-2026-53193 https://www.cve.org/CVERecord?id=CVE-2026-53193 Référence CVE CVE-2026-53195 https://www.cve.org/CVERecord?id=CVE-2026-53195 Référence CVE CVE-2026-53196 https://www.cve.org/CVERecord?id=CVE-2026-53196 Référence CVE CVE-2026-53199 https://www.cve.org/CVERecord?id=CVE-2026-53199 Référence CVE CVE-2026-53202 https://www.cve.org/CVERecord?id=CVE-2026-53202 Référence CVE CVE-2026-53203 https://www.cve.org/CVERecord?id=CVE-2026-53203 Référence CVE CVE-2026-53205 https://www.cve.org/CVERecord?id=CVE-2026-53205 Référence CVE CVE-2026-53208 https://www.cve.org/CVERecord?id=CVE-2026-53208 Référence CVE CVE-2026-53209 https://www.cve.org/CVERecord?id=CVE-2026-53209 Référence CVE CVE-2026-53210 https://www.cve.org/CVERecord?id=CVE-2026-53210 Référence CVE CVE-2026-53212 https://www.cve.org/CVERecord?id=CVE-2026-53212 Référence CVE CVE-2026-53213 https://www.cve.org/CVERecord?id=CVE-2026-53213 Référence CVE CVE-2026-53214 https://www.cve.org/CVERecord?id=CVE-2026-53214 Référence CVE CVE-2026-53218 https://www.cve.org/CVERecord?id=CVE-2026-53218 Référence CVE CVE-2026-53221 https://www.cve.org/CVERecord?id=CVE-2026-53221 Référence CVE CVE-2026-53224 https://www.cve.org/CVERecord?id=CVE-2026-53224 Référence CVE CVE-2026-53225 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0927Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2026-53186 Référence CVE CVE-2026-53190 https://www.cve.org/CVERecord?id=CVE-2026-53190 Référence CVE CVE-2026-53192 https://www.cve.org/CVERecord?id=CVE-2026-53192 Référence CVE CVE-2026-53194 https://www.cve.org/CVERecord?id=CVE-2026-53194 Référence CVE CVE-2026-53195 https://www.cve.org/CVERecord?id=CVE-2026-53195 Référence CVE CVE-2026-53196 https://www.cve.org/CVERecord?id=CVE-2026-53196 Référence CVE CVE-2026-53202 https://www.cve.org/CVERecord?id=CVE-2026-53202 Référence CVE CVE-2026-53203 https://www.cve.org/CVERecord?id=CVE-2026-53203 Référence CVE CVE-2026-53208 https://www.cve.org/CVERecord?id=CVE-2026-53208 Référence CVE CVE-2026-53209 https://www.cve.org/CVERecord?id=CVE-2026-53209 Référence CVE CVE-2026-53213 https://www.cve.org/CVERecord?id=CVE-2026-53213 Référence CVE CVE-2026-53215 https://www.cve.org/CVERecord?id=CVE-2026-53215 Référence CVE CVE-2026-53216 https://www.cve.org/CVERecord?id=CVE-2026-53216 Référence CVE CVE-2026-53217 https://www.cve.org/CVERecord?id=CVE-2026-53217 Référence CVE CVE-2026-53218 https://www.cve.org/CVERecord?id=CVE-2026-53218 Référence CVE CVE-2026-53224 https://www.cve.org/CVERecord?id=CVE-2026-53224 Référence CVE CVE-2026-53225 https://www.cve.org/CVERecord?id=CVE-2026-53225 Référence CVE CVE-2026-53227 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0862Multiples vulnérabilités dans le noyau Linux de Debian LTS

d?id=CVE-2026-53186 Référence CVE CVE-2026-53189 https://www.cve.org/CVERecord?id=CVE-2026-53189 Référence CVE CVE-2026-53194 https://www.cve.org/CVERecord?id=CVE-2026-53194 Référence CVE CVE-2026-53195 https://www.cve.org/CVERecord?id=CVE-2026-53195 Référence CVE CVE-2026-53196 https://www.cve.org/CVERecord?id=CVE-2026-53196 Référence CVE CVE-2026-53198 https://www.cve.org/CVERecord?id=CVE-2026-53198 Référence CVE CVE-2026-53199 https://www.cve.org/CVERecord?id=CVE-2026-53199 Référence CVE CVE-2026-53207 https://www.cve.org/CVERecord?id=CVE-2026-53207 Référence CVE CVE-2026-53208 https://www.cve.org/CVERecord?id=CVE-2026-53208 Référence CVE CVE-2026-53209 https://www.cve.org/CVERecord?id=CVE-2026-53209 Référence CVE CVE-2026-53212 https://www.cve.org/CVERecord?id=CVE-2026-53212 Référence CVE CVE-2026-53213 https://www.cve.org/CVERecord?id=CVE-2026-53213 Référence CVE CVE-2026-53215 https://www.cve.org/CVERecord?id=CVE-2026-53215 Référence CVE CVE-2026-53216 https://www.cve.org/CVERecord?id=CVE-2026-53216 Référence CVE CVE-2026-53217 https://www.cve.org/CVERecord?id=CVE-2026-53217 Référence CVE CVE-2026-53218 https://www.cve.org/CVERecord?id=CVE-2026-53218 Référence CVE CVE-2026-53219 https://www.cve.org/CVERecord?id=CVE-2026-53219 Référence CVE CVE-2026-53221 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0812Multiples vulnérabilités dans Microsoft Azure Linux

ulletin de sécurité Microsoft CVE-2026-53177 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53181 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53182 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53183 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53184 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53186 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53194 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53196 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53199 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53207 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53209 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53213 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53214 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53215 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53217 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53218 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53219 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53221 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53225 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53227 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53228 du 27 juin 2026 Bulletin de s

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-022342LinuxのLinux Kernelにおける境界外書き込みに関する脆弱性

Linuxカーネルにおいて、以下の脆弱性が解消されました:Bluetooth: hci_sync: サイズ超過となる Broadcast Announcement の前置を拒否既存のアドバタイジングインスタンスは、すでに拡張アドバタイジングの最大ペイロードを保持している場合があります。hci_adv_bcast_annoucement() がそのペイロードに Broadcast Announcement のサービスデータを前置すると、結合後のデータがアドバタイジングデータを再構築するための一時バッファに収まりきらない可能性があります。既存のペイロードをコピーする前にそのケースを拒否し、デバイスログで失敗を報告します。これにより既存のアドバタイジングデータはそのまま保持され、一時バッファのオーバーランを回避できます。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 25 Jun 2026 · Last source change 5 Aug 2026, 12:34 UTC · CWE-787 · Out-of-bounds Write

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-39300
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceNIST NVD
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-39300↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Patch or update reference↗Patch or update reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-53209 · cve.blacktree.nl