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VulnerabilityPublished Updated

CVE-2026-31682: Linux kernel · bridge: br_nd_send: linearize skb before parsing ND options

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2026-31682· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical · fixed in 4.15.0-1205.220~14.04.1 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.15.0-1205.220~14.04.1, 4.15.0-1194.207~16.04.1, 4.15.0-1204.219~16.04.1 +116
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde@7.0.0-1008.8?arch=source&distro=resoluteOther threatsAffected
  • 7.0.0-1003.3 – 7.0.0-1008.8
4 affected builds
Fixed in–
Ubuntu 26.04 LTSlinux-nvidiapkg:deb/ubuntu/linux-nvidia?arch=source&distro=resoluteOther threatsAffected
  • <7.0.0-1006.6
Fixed in
  • 7.0.0-1006.6
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threatsAffected
  • <6.17.0-40.40
Fixed in
  • 6.17.0-40.40
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1019.19
Fixed in
  • 6.17.0-1019.19
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threatsAffected
  • 6.14.0-1004.4 – 6.17.0-1020.20
16 affected builds
Fixed in–
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

An official patch is available and should be applied promptly. The Ubuntu security advisories USN-8490-1 and USN-8491-1 provide updated Linux kernel packages that fix this and other vulnerabilities. After applying the kernel update, a system reboot is required. Note that due to ABI changes, third-party kernel modules must be recompiled and reinstalled. Users should update to the fixed kernel versions as specified in the vendor advisories to fully mitigate this vulnerability.

Description

A vulnerability in the Linux kernel's bridge networking code (br_nd_send function) was resolved. The issue involved improper handling of neighbor discovery (ND) options in IPv6 packets, where the code assumed these options were in a linear buffer area, but they could be non-linear. This could lead to out-of-bounds memory access. The vulnerability affects multiple Linux Azure kernel versions prior to specified patched releases. A high-severity CVSS 3.1 score of 9.1 is assigned. Official patches are available and should be applied to mitigate the risk.

References

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