CVE-2026-72400: Linux kernel · seg6: validate SRH length before reading fixed fields
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 that corrects the vulnerability by validating the SRH length before accessing fixed fields. Users should apply the updated Linux kernel versions that include this fix. No additional mitigation is required beyond applying the official patch.
Description
A vulnerability in the Linux kernel's seg6_validate_srh() function allowed reading beyond the supplied buffer due to insufficient validation of the SRH length before accessing fixed fields. This issue affected the BPF SEG6 encap path, where a crafted 2-byte SEG6 encap header could cause out-of-bounds reads. The vulnerability has been fixed by adding a length check before any field access in seg6_validate_srh().
References
- nvd.nist.gov/vuln/detail/CVE-2026-72400 (opens in a new tab)
- git.kernel.org/stable/c/071f1a38d7ddbadee29c09b9e3ee0ff3a61e6a0e (opens in a new tab)
- git.kernel.org/stable/c/0fc7069d39239978130c37ebceaec85c8948d3f1 (opens in a new tab)
- git.kernel.org/stable/c/715eb12e453df752f1b4baaf972c3acff0ab9402 (opens in a new tab)
- git.kernel.org/stable/c/7247d05c987c3eec4bb7c2306dbd77ecdf3b7c73 (opens in a new tab)
- git.kernel.org/stable/c/804bb969f194c93497ba632b98343794c6367fdc (opens in a new tab)
- git.kernel.org/stable/c/8dba7a94a269b88e500aafc25ad567ef6a423698 (opens in a new tab)
- git.kernel.org/stable/c/a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa (opens in a new tab)
- git.kernel.org/stable/c/c9961336aa5ff83092f23e33ee86666a9dbd1b2a (opens in a new tab)
- ubuntu.com/security/CVE-2026-72400 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72400 (opens in a new tab)
- git.kernel.org/linus/a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa (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)