CVE-2026-43451: Linux kernel · netfilter: nfnetlink_queue: fix entry leak in bridge verdict error path
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · patch available : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde@7.0.0-1008.8?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected linux-azure kernel versions. The fix properly frees leaked resources on error paths in nfnetlink_queue. Users should update to patched kernel versions as provided by their vendor. No additional mitigation is required beyond applying the official fix.
Description
A memory leak vulnerability in the Linux kernel's netfilter nfnetlink_queue subsystem was fixed. The issue occurs when parsing VLAN attributes for PF_BRIDGE packets, where an error path fails to free allocated queue entries and associated resources, leading to kernel memory exhaustion. This vulnerability affects specific linux-azure kernel versions and has a medium severity rating with a CVSS score of 5.5. A patch is available to address the issue by properly dropping the entry on error. No known exploits are reported in the wild.
References
- ubuntu.com/security/CVE-2026-43451 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43451 (opens in a new tab)
- git.kernel.org/linus/f1ba83755d81c6fc66ac7acd723d238f974091e9 (opens in a new tab)
- git.kernel.org/stable/c/0b18d1b834ab5a5009be70b530f978d7989e445b (opens in a new tab)
- git.kernel.org/stable/c/208669df703a25a601f45822b10c413f258bf275 (opens in a new tab)
- git.kernel.org/stable/c/47b1c5d1b0944aa88299f55a846fabaefc756982 (opens in a new tab)
- git.kernel.org/stable/c/9853d94b82d303fc4ac37d592a23a154096ecd41 (opens in a new tab)
- git.kernel.org/stable/c/a907bea273b60d3e604ec4e8e1f6c49954805794 (opens in a new tab)
- git.kernel.org/stable/c/b38d2b4603fd3dda24eb8b3dd81c18a0930be97b (opens in a new tab)
- git.kernel.org/stable/c/cf4a4df38d1747e06fc54f9879bd7a6f4178032f (opens in a new tab)
- git.kernel.org/stable/c/f1ba83755d81c6fc66ac7acd723d238f974091e9 (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)