CVE-2026-72400
In the Linux kernel, the following vulnerability has been resolved: seg6: validate SRH length before reading fixed fields seg6_validate_srh() reads fixed SRH fields such as srh->type and srh->hdrlen before checking that the supplied length covers the fixed struct ipv6_sr_hdr fields. The BPF SEG6 encap path reaches this with a BPF program-supplied pointer and length: bpf_lwt_push_encap() and the SEG6 local BPF END_B6 and END_B6_ENCAP actions call bpf_push_seg6_encap(), which forwards the length to seg6_validate_srh() with no minimum-size guard. A 2-byte SEG6 encap header can therefore make the validator read srh->type at offset 2 beyond the caller-supplied buffer. Reject lengths shorter than the fixed SRH at the top of seg6_validate_srh(), before any field is read. This fixes the BPF helper path and keeps the common validator robust.
Affected versions
Linux kernel versions
4.18
and later are affected. Fixed in
5.10.261,
5.15.212,
6.1.178,
6.6.145,
6.12.97,
6.18.40,
7.1.5,
7.2-rc2
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-72400?
CVE-2026-72400 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 4.18 onward and has been patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-72400 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-72400?
Yes. CVE-2026-72400 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 4.18 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-72400 actively exploited?
No. CVE-2026-72400 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.