CVE-2026-43373: Linux kernel · net: ncsi: fix skb leak in error paths
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High · patch available : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:N/AC:L/PR:N/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 addressing this memory leak vulnerability is available and should be applied. The vendor advisory from Ubuntu confirms that fixes have been released for affected linux-azure kernel versions. Users should update to the patched kernel versions to remediate this issue.
Description
A memory leak vulnerability was identified and fixed in the Linux kernel's Network Controller Sideband Interface (NCSI) implementation used in the linux-azure kernel. The issue occurs because early return paths in the NCSI RX and Asynchronous Event Notification (AEN) handlers fail to release received socket buffers (skb), causing memory to be leaked. This affects specific linux-azure kernel versions. The vulnerability has a CVSS score of 7.5 with a medium severity rating and does not impact confidentiality or integrity but affects availability due to resource exhaustion. A patch is available to address this issue.
References
- ubuntu.com/security/CVE-2026-43373 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43373 (opens in a new tab)
- git.kernel.org/linus/5c3398a54266541610c8d0a7082e654e9ff3e259 (opens in a new tab)
- git.kernel.org/stable/c/553366c271479c0d571dd1bb5d1bcde4747fb82e (opens in a new tab)
- git.kernel.org/stable/c/59962588197863d0d746879f193905c0c6b3df49 (opens in a new tab)
- git.kernel.org/stable/c/5c3398a54266541610c8d0a7082e654e9ff3e259 (opens in a new tab)
- git.kernel.org/stable/c/81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a (opens in a new tab)
- git.kernel.org/stable/c/87138dde2d6937b12b967f28fe598a7d59000ae4 (opens in a new tab)
- git.kernel.org/stable/c/9891d7f4f1ede473c54b49776ae07755083eef06 (opens in a new tab)
- git.kernel.org/stable/c/b70c4e5e711931cdd56e6e905737b72f1e649189 (opens in a new tab)
- git.kernel.org/stable/c/fef5aa6e3bcf3c8053307642663a63b7362d7552 (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)