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Full vulnerability report · 2026
CVE-2026-53263High confidence

6lowpan: fix off-by-one in multicast context address compression

Linux · Linux

5.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 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 8 Sept 2026
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-2026-39214

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 actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

In the Linux kernel, the following vulnerability has been resolved: 6lowpan: fix off-by-one in multicast context address compression The second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses &data[1] as destination and &ipaddr->s6_addr[11] as source, but both should be offset by one: &data[2] and &ipaddr->s6_addr[12] respectively. This off-by-one has two consequences: 1. data[1] is overwritten with s6_addr[11], corrupting the RIID field in the compressed multicast address 2. data[5] is never written, so uninitialized kernel stack memory is transmitted over the network via lowpan_push_hc_data(), leaking kernel stack contents The correct inline data layout must match what the decompression function lowpan_uncompress_multicast_ctx_daddr() expects: data[0..1] = s6_addr[1..2] (flags/scope + RIID) data[2..5] = s6_addr[12..15] (group ID) Also zero-initialize the data array as a defensive measure against similar bugs in the future.

What

In the Linux kernel, the following vulnerability has been resolved: 6lowpan: fix off-by-one in multicast context address compression The second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses &data[1] as destination and &ipaddr->s6_addr[11] as source, but both should be offset by one: &data[2] and &ipaddr->s6_addr[12] respectively. This off-by-one has two consequences: 1. data[1] is overwritten with s6_addr[11], corrupting the RIID field in the compressed multicast address 2. data[5] is never written, so uninitialized kernel stack memory is transmitted over the network via lowpan_push_hc_data(), leaking kernel stack contents The correct inline data layout must match what the decompression function lowpan_uncompress_multicast_ctx_daddr() expects: data[0..1] = s6_addr[1..2] (flags/scope + RIID) data[2..5] = s6_addr[12..15] (group ID) Also zero-initialize the data array as a defensive measure against similar bugs in the future.

Why

A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

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: 6lowpan: fix off-by-one in multicast context address compression The second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses &data[1] as destination and &ipaddr->s6_addr[11] as source, but both should be offset by one: &data[2] and &ipaddr->s6_addr[12] respectively. This off-by-one has two consequences: 1. data[1] is overwritten with s6_addr[11], corrupting the RIID field in the compressed multicast address 2. data[5] is never written, so uninitialized kernel stack memory is transmitted over the network via lowpan_push_hc_data(), leaking kernel stack contents The correct inline data layout must match what the decompression function lowpan_uncompress_multicast_ctx_daddr() expects: data[0..1] = s6_addr[1..2] (flags/scope + RIID) data[2..5] = s6_addr[12..15] (group ID) Also zero-initialize the data array as a defensive measure against similar bugs in the future.

Why

A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

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 → Off-by-one Error → 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-193

CWE-193: Off-by-one Error. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

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:N/I:N/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.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.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-193
A

Official authority intelligence

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

BSI · German · WID-SEC-W-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
CERT-FR · French · CERTFR-2026-AVI-0956Multiples vulnérabilités dans le noyau Linux de SUSE

d?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-2026-53229 https://www.cve.org/CVERecord?id=CVE-2026-53229 Référence CVE CVE-2026-53245 https://www.cve.org/CVERecord?id=CVE-2026-53245 Référence CVE CVE-2026-53249 https://www.cve.org/CVERecord?id=CVE-2026-53249 Référence CVE CVE-2026-53256 https://www.cve.org/CVERecord?id=CVE-2026-53256 Référence CVE CVE-2026-53258 https://www.cve.org/CVERecord?id=CVE-2026-53258 Référence CVE CVE-2026-53262 https://www.cve.org/CVERecord?id=CVE-2026-53262 Référence CVE CVE-2026-53263 https://www.cve.org/CVERecord?id=CVE-2026-53263 Référence CVE CVE-2026-53266 https://www.cve.org/CVERecord?id=CVE-2026-53266 Référence CVE CVE-2026-53272 https://www.cve.org/CVERecord?id=CVE-2026-53272 Référence CVE CVE-2026-53274 https://www.cve.org/CVERecord?id=CVE-2026-53274 Référence CVE CVE-2026-53281 https://www.cve.org/CVERecord?id=CVE-2026-53281 Référence CVE CVE-2026-53285 https://www.cve.org/CVERecord?id=CVE-2026-53285 Référence CVE CVE-2026-53286 https://www.cve.org/CVERecord?id=CVE-2026-53286 Référence CVE CVE-2026-53287 https://www.cve.org/CVERecord?id=CVE-2026-53287 Référence CVE CVE-2026-53306 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-2026-53245 Référence CVE CVE-2026-53246 https://www.cve.org/CVERecord?id=CVE-2026-53246 Référence CVE CVE-2026-53249 https://www.cve.org/CVERecord?id=CVE-2026-53249 Référence CVE CVE-2026-53253 https://www.cve.org/CVERecord?id=CVE-2026-53253 Référence CVE CVE-2026-53254 https://www.cve.org/CVERecord?id=CVE-2026-53254 Référence CVE CVE-2026-53255 https://www.cve.org/CVERecord?id=CVE-2026-53255 Référence CVE CVE-2026-53256 https://www.cve.org/CVERecord?id=CVE-2026-53256 Référence CVE CVE-2026-53258 https://www.cve.org/CVERecord?id=CVE-2026-53258 Référence CVE CVE-2026-53262 https://www.cve.org/CVERecord?id=CVE-2026-53262 Référence CVE CVE-2026-53263 https://www.cve.org/CVERecord?id=CVE-2026-53263 Référence CVE CVE-2026-53266 https://www.cve.org/CVERecord?id=CVE-2026-53266 Référence CVE CVE-2026-53268 https://www.cve.org/CVERecord?id=CVE-2026-53268 Référence CVE CVE-2026-53272 https://www.cve.org/CVERecord?id=CVE-2026-53272 Référence CVE CVE-2026-53274 https://www.cve.org/CVERecord?id=CVE-2026-53274 Référence CVE CVE-2026-53279 https://www.cve.org/CVERecord?id=CVE-2026-53279 Référence CVE CVE-2026-53281 https://www.cve.org/CVERecord?id=CVE-2026-53281 Référence CVE CVE-2026-53285 https://www.cve.org/CVERecord?id=CVE-2026-53285 Référence CVE CVE-2026-53286 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-2026-53239 Référence CVE CVE-2026-53242 https://www.cve.org/CVERecord?id=CVE-2026-53242 Référence CVE CVE-2026-53245 https://www.cve.org/CVERecord?id=CVE-2026-53245 Référence CVE CVE-2026-53249 https://www.cve.org/CVERecord?id=CVE-2026-53249 Référence CVE CVE-2026-53252 https://www.cve.org/CVERecord?id=CVE-2026-53252 Référence CVE CVE-2026-53253 https://www.cve.org/CVERecord?id=CVE-2026-53253 Référence CVE CVE-2026-53254 https://www.cve.org/CVERecord?id=CVE-2026-53254 Référence CVE CVE-2026-53255 https://www.cve.org/CVERecord?id=CVE-2026-53255 Référence CVE CVE-2026-53256 https://www.cve.org/CVERecord?id=CVE-2026-53256 Référence CVE CVE-2026-53263 https://www.cve.org/CVERecord?id=CVE-2026-53263 Référence CVE CVE-2026-53264 https://www.cve.org/CVERecord?id=CVE-2026-53264 Référence CVE CVE-2026-53266 https://www.cve.org/CVERecord?id=CVE-2026-53266 Référence CVE CVE-2026-53268 https://www.cve.org/CVERecord?id=CVE-2026-53268 Référence CVE CVE-2026-53269 https://www.cve.org/CVERecord?id=CVE-2026-53269 Référence CVE CVE-2026-53270 https://www.cve.org/CVERecord?id=CVE-2026-53270 Référence CVE CVE-2026-53273 https://www.cve.org/CVERecord?id=CVE-2026-53273 Référence CVE CVE-2026-53274 https://www.cve.org/CVERecord?id=CVE-2026-53274 Référence CVE CVE-2026-53275 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-2026-53238 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53239 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53242 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53245 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53247 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53249 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53252 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53253 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53254 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53255 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53263 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53264 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53265 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53266 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53267 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53268 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53270 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53274 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-53275 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-55200 du 27 juin 2026 Bulletin de sécurité Microsoft CVE-2026-9675 du 27 juin 2026 Bulletin de sé

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
5609c185f24dffca5f6a9c127106869da150be03 < f24a58c72a45f4c109f3557a760cc4b60b7a6037; 5609c185f24dffca5f6a9c127106869da150be03 < da8cbb64b47e9066b40af0de170901caf17b768c; 5609c185f24dffca5f6a9c127106869da150be03 < 4485d79617520d84ba5a14515e2b5136007d6deb; 5609c185f24dffca5f6a9c127106869da150be03 < 06ce6fc106b16dec9b535950db626261be865e5b; 5609c185f24dffca5f6a9c127106869da150be03 < dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af; 5609c185f24dffca5f6a9c127106869da150be03 < c32f30ef5e66adbfa102348e2e8a23776eb007cb; 5609c185f24dffca5f6a9c127106869da150be03 < da8808463882c3f3c357b072e25053c2121f1419; 5609c185f24dffca5f6a9c127106869da150be03 < 2a58899d11009bffc7b4b32a571858f381121837
Fixed
< 4.6; 5.10.259 ≤ 5.10.*; 5.15.210 ≤ 5.15.*; 6.1.176 ≤ 6.1.*; 6.6.143 ≤ 6.6.*; 6.12.94 ≤ 6.12.*; 6.18.36 ≤ 6.18.*; 7.0.13 ≤ 7.0.*
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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 25 Jun 2026, 08:39 UTC · CWE-193 · Off-by-one Error

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
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-2026-39214
Product sourceCNA
Remediation sourceCVE/CNA references
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
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-2026-53263 · cve.blacktree.nl