CVE-2026-72350: Linux kernel · netfilter: xt_u32: reject invalid shift counts
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +42
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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
An official patch is available and should be applied to affected Linux kernel versions. The vendor advisory confirms that the issue has been fixed by validating shift operands and rejecting malformed rules before packet evaluation. Users should update to patched kernel versions to mitigate this vulnerability.
Description
A vulnerability in the Linux kernel's netfilter xt_u32 module allowed malformed rules with invalid shift counts (32 or more) to trigger undefined behavior during packet evaluation. This could lead to system compromise. The issue has been fixed by validating and rejecting malformed shift operands before packet processing.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72350 (opens in a new tab)
- git.kernel.org/stable/c/00d034fe8230dfc5832fe011ff2d81c1a2cc7a29 (opens in a new tab)
- git.kernel.org/stable/c/0a8b7a6d763775709c601f584e709ae48bcc000a (opens in a new tab)
- git.kernel.org/stable/c/64cdf7d30ac18e43df6c48004435febb965809a8 (opens in a new tab)
- git.kernel.org/stable/c/728f479dc0447ae7eaef87926ff49142e415a811 (opens in a new tab)
- git.kernel.org/stable/c/a597a722fb71a534138c20359b655726622b5f17 (opens in a new tab)
- git.kernel.org/stable/c/b33b44250d57ab0e5a1e2571b5285fb0d0a7f382 (opens in a new tab)
- git.kernel.org/stable/c/ca7c92d9701249e6daf132087756a88cbf2bb2a3 (opens in a new tab)
- git.kernel.org/stable/c/cce42014415cecd98aa49b3950e7b02ee7c81268 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72350 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72350 (opens in a new tab)
- git.kernel.org/linus/64cdf7d30ac18e43df6c48004435febb965809a8 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)