BlackTreeIndependent security intelligence

Full vulnerability report · 2026

CVE-2026-72253High confidence

netfilter: nf_conntrack_sip: validate skb_dst() before accessing it

Linux · Linux

7.5HighCVSS 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 release	Source package	Vendor state	Fixed version	Evidence
Ubuntu 24.04 LTSnoble · standard archive	`linux`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-aws`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure-fde`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure-nvidia`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gcp`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gke`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gkeop`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-ibm`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-lowlatency`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia-lowlatency`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia-tegra`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-oem-6.11`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-oracle`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi-realtime`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-realtime`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-riscv`	Affected, 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 feed`	Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-xilinx`	Affected, 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 feed`	Canonical record ↗Source updated 9 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-2026-72253 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitykernel: netfilter: nf_conntrack_sip: validate skb_dst() before accessing it

274 known affected

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

kernel as a component of Red Hat Enterprise Linux 10
kernel-64k as a component of Red Hat Enterprise Linux 10
kernel-64k-core as a component of Red Hat Enterprise Linux 10
kernel-64k-debug as a component of Red Hat Enterprise Linux 10
kernel-64k-debug-core as a component of Red Hat Enterprise Linux 10
kernel-64k-debug-devel as a component of Red Hat Enterprise Linux 10
kernel-64k-debug-devel-matched as a component of Red Hat Enterprise Linux 10
kernel-64k-debug-modules as a component of Red Hat Enterprise Linux 10
kernel-64k-debug-modules-core as a component of Red Hat Enterprise Linux 10
kernel-64k-debug-modules-extra as a component of Red Hat Enterprise Linux 10
kernel-64k-devel as a component of Red Hat Enterprise Linux 10
kernel-64k-devel-matched as a component of Red Hat Enterprise Linux 10

Summary: A flaw was found in the Linux kernel's Netfilter Session Initiation Protocol (SIP) connection tracking helper. This vulnerability occurs when network traffic control (tc ingress) or Open vSwitch (openvswitch) subsystems are active, and a specific media handling feature (`sip_external_media`) is enabled. The system fails to properly verify network routing information, which can lead to the `sip_external_media` feature being unintentionally disabled, impacting its intended operation.
Remediation: Affected

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-2026-59152

No EUVD known-exploited evidence

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: validate skb_dst() before accessing it tc ingress and openvswitch do not guarantee routing information to be available. These subsystems use the conntrack helper infrastructure, and the SIP helper relies on the skb_dst() to be present if sip_external_media is set to 1 (which is disabled by default as a module parameter). This effectively disables the sip_external_media toggle for these subsystems without resulting in a crash.

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: 7.5 · CVSS 3.1
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

What, why and how

What

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

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: a network path → vulnerable operation → disrupt the affected service
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
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.: CWE not yet assigned
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:L/PR:N/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.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing 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: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkUnauthenticatedDenial of service

Official authority intelligence

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

ENISA EUVD · EUVD-2026-59152Official EUVD mapping

Official EUVD record

BSI · German · WID-SEC-W-2026-2852Linux Kernel: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um einen Denial of Service herbeizuführen oder einen nicht näher spezifizierten Angriff durchzuführen.

Official advisory

CERT-FR · French · CERTFR-2026-AVI-1069Multiples vulnérabilités dans le noyau Linux de Debian LTS

d?id=CVE-2026-72137 Référence CVE CVE-2026-72142 https://www.cve.org/CVERecord?id=CVE-2026-72142 Référence CVE CVE-2026-72146 https://www.cve.org/CVERecord?id=CVE-2026-72146 Référence CVE CVE-2026-72147 https://www.cve.org/CVERecord?id=CVE-2026-72147 Référence CVE CVE-2026-72168 https://www.cve.org/CVERecord?id=CVE-2026-72168 Référence CVE CVE-2026-72175 https://www.cve.org/CVERecord?id=CVE-2026-72175 Référence CVE CVE-2026-72183 https://www.cve.org/CVERecord?id=CVE-2026-72183 Référence CVE CVE-2026-72213 https://www.cve.org/CVERecord?id=CVE-2026-72213 Référence CVE CVE-2026-72244 https://www.cve.org/CVERecord?id=CVE-2026-72244 Référence CVE CVE-2026-72253 https://www.cve.org/CVERecord?id=CVE-2026-72253 Référence CVE CVE-2026-72254 https://www.cve.org/CVERecord?id=CVE-2026-72254 Référence CVE CVE-2026-72260 https://www.cve.org/CVERecord?id=CVE-2026-72260 Référence CVE CVE-2026-72299 https://www.cve.org/CVERecord?id=CVE-2026-72299 Référence CVE CVE-2026-72305 https://www.cve.org/CVERecord?id=CVE-2026-72305 Référence CVE CVE-2026-72372 https://www.cve.org/CVERecord?id=CVE-2026-72372 Référence CVE CVE-2026-74436 https://www.cve.org/CVERecord?id=CVE-2026-74436 Gestion détaillée du document le 21 août 2026 Version initiale Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À

Official advisory

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: kernel as a component of Red Hat Enterprise Linux 10; kernel-64k as a component of Red Hat Enterprise Linux 10; kernel-64k-core as a component of Red Hat Enterprise Linux 10; kernel-64k-debug as a component of Red Hat Enterprise Linux 10; kernel-64k-debug-core as a component of Red Hat Enterprise Linux 10; kernel-64k-debug-devel as a component of Red Hat Enterprise Linux 10; kernel-64k-debug-devel-matched as a component of Red Hat Enterprise Linux 10; kernel-64k-debug-modules as a component of Red Hat Enterprise Linux 10; kernel-64k-debug-modules-core as a component of Red Hat Enterprise Linux 10; kernel-64k-debug-modules-extra as a component of Red Hat Enterprise Linux 10; kernel-64k-devel as a component of Red Hat Enterprise Linux 10; kernel-64k-devel-matched as a component of Red Hat Enterprise Linux 10; kernel-64k-modules as a component of Red Hat Enterprise Linux 10; kernel-64k-modules-core as a component of Red Hat Enterprise Linux 10; kernel-64k-modules-extra as a component of Red Hat Enterprise Linux 10; kernel-abi-stablelists as a component of Red Hat Enterprise Linux 10; kernel-core as a component of Red Hat Enterprise Linux 10; kernel-debug as a component of Red Hat Enterprise Linux 10; kernel-debug-core as a component of Red Hat Enterprise Linux 10; kernel-debug-devel as a component of Red Hat Enterprise Linux 10; kernel-debug-devel-matched as a component of Red Hat Enterprise Linux 10; kernel-debug-modules as a component of Red Hat Enterprise Linux 10; kernel-debug-modules-core as a component of Red Hat Enterprise Linux 10; kernel-debug-modules-extra as a component of Red Hat Enterprise Linux 10; kernel-debug-uki-virt as a component of Red Hat Enterprise Linux 10; kernel-devel as a component of Red Hat Enterprise Linux 10; kernel-devel-matched as a component of Red Hat Enterprise Linux 10; kernel-doc as a component of Red Hat Enterprise Linux 10; kernel-modules as a component of Red Hat Enterprise Linux 10; kernel-modules-core as a component of Red Hat Enterprise Linux 10; and 244 more
Fixed: < 4.3; 5.10.266 ≤ 5.10.*; 5.15.217 ≤ 5.15.*; 6.1.184 ≤ 6.1.*; 6.6.148 ≤ 6.6.*; 6.12.101 ≤ 6.12.*; 6.18.42 ≤ 6.18.*; 7.1.5 ≤ 7.1.*
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 15 Aug 2026 · Last source change 23 Aug 2026, 12:47 UTC · CWE not yet assigned

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 2026-08-23

European sourceENISA EUVD · EUVD-2026-59152

Product sourceVendor CSAF · Red Hat Product Security

Remediation sourceVendor CSAF · Red Hat Product Security

CWE sourceUnavailable

NVD statusNVD received

Missing structured fields: CWE classification. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates →

23 Aug 2026, 12:47 UTC
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link to authoritative remediation link.
Before
authoritative remediation link
After
authoritative remediation link
CNA ↗
23 Aug 2026, 12:47 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
cae3a2627520c3795b54533c5328b77af3405dbe < e64a48c50a1ff565a98c6a98d82b5b942868e76e; cae3a2627520c3795b54533c5328b77af3405dbe < c199ed687c00841daf60e9d131976958583a8c09; cae3a2627520c3795b54533c5328b77af3405dbe < 09755dc62b026076b1d47f83489eb0547c8135e0; cae3a2627520c3795b54533c5328b77af3405dbe < b843a96252f672332837ea2ecb7c8db0acf68e20; cae3a2627520c3795b54533c5328b77af3405dbe < e5e24a365a5e024efef63cc49abb345fbd4852c5; 4.3 · Fixed: < 4.3; 6.6.148 ≤ 6.6.*; 6.12.101 ≤ 6.12.*; 6.18.42 ≤ 6.18.*; 7.1.5 ≤ 7.1.*; 7.2 ≤ *
After
cae3a2627520c3795b54533c5328b77af3405dbe < 7866116a040b3a23fb094e7d8f7ea3d61b3ac70b; cae3a2627520c3795b54533c5328b77af3405dbe < c5ef7228be04518d95591fc5369a9c554b19756d; cae3a2627520c3795b54533c5328b77af3405dbe < 0aec339694a56e263d4b22475ff7211d40900830; cae3a2627520c3795b54533c5328b77af3405dbe < e64a48c50a1ff565a98c6a98d82b5b942868e76e; cae3a2627520c3795b54533c5328b77af3405dbe < c199ed687c00841daf60e9d131976958583a8c09; cae3a2627520c3795b54533c5328b77af3405dbe < 09755dc62b026076b1d47f83489eb0547c8135e0; cae3a2627520c3795b54533c5328b77af3405dbe < b843a96252f672332837ea2ecb7c8db0acf68e20; cae3a2627520c3795b54533c5328b77af3405dbe < e5e24a365a5e024efef63cc49abb345fbd4852c5 · Fixed: < 4.3; 5.10.266 ≤ 5.10.*; 5.15.217 ≤ 5.15.*; 6.1.184 ≤ 6.1.*; 6.6.148 ≤ 6.6.*; 6.12.101 ≤ 6.12.*; 6.18.42 ≤ 6.18.*; 7.1.5 ≤ 7.1.*
CNA ↗
17 Aug 2026, 05:42 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
cae3a2627520c3795b54533c5328b77af3405dbe < e64a48c50a1ff565a98c6a98d82b5b942868e76e; cae3a2627520c3795b54533c5328b77af3405dbe < c199ed687c00841daf60e9d131976958583a8c09; cae3a2627520c3795b54533c5328b77af3405dbe < 09755dc62b026076b1d47f83489eb0547c8135e0; cae3a2627520c3795b54533c5328b77af3405dbe < b843a96252f672332837ea2ecb7c8db0acf68e20; cae3a2627520c3795b54533c5328b77af3405dbe < e5e24a365a5e024efef63cc49abb345fbd4852c5; 4.3 · Fixed: < 4.3; 6.6.148 ≤ 6.6.*; 6.12.101 ≤ 6.12.*; 6.18.42 ≤ 6.18.*; 7.1.5 ≤ 7.1.*; 7.2-rc2 ≤ *
After
cae3a2627520c3795b54533c5328b77af3405dbe < e64a48c50a1ff565a98c6a98d82b5b942868e76e; cae3a2627520c3795b54533c5328b77af3405dbe < c199ed687c00841daf60e9d131976958583a8c09; cae3a2627520c3795b54533c5328b77af3405dbe < 09755dc62b026076b1d47f83489eb0547c8135e0; cae3a2627520c3795b54533c5328b77af3405dbe < b843a96252f672332837ea2ecb7c8db0acf68e20; cae3a2627520c3795b54533c5328b77af3405dbe < e5e24a365a5e024efef63cc49abb345fbd4852c5; 4.3 · Fixed: < 4.3; 6.6.148 ≤ 6.6.*; 6.12.101 ≤ 6.12.*; 6.18.42 ≤ 6.18.*; 7.1.5 ≤ 7.1.*; 7.2 ≤ *
CNA ↗
17 Aug 2026, 05:42 UTC
SeveritySeverity changed from Unknown to High.
Before
Unknown
After
High
CNA ↗
17 Aug 2026, 05:42 UTC
CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Before
not recorded
After
7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CNA ↗
15 Aug 2026, 05:54 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2026-08-15CVE published

2026-08-23Fixed release or patch reference recorded

ENISA EUVD · EUVD-2026-59152↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor 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.