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CVE-2026-72400

seg6: validate SRH length before reading fixed fields

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in 715eb12e453df752f1b4baaf972c3acff0ab9402; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in 7247d05c987c3eec4bb7c2306dbd77ecdf3b7c73; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in 071f1a38d7ddbadee29c09b9e3ee0ff3a61e6a0e; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in 804bb969f194c93497ba632b98343794c6367fdc; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in 0fc7069d39239978130c37ebceaec85c8948d3f1; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in 8dba7a94a269b88e500aafc25ad567ef6a423698; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in c9961336aa5ff83092f23e33ee86666a9dbd1b2a; From fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 · fixed in a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa

  • Linux Linux

    4.18

  • KernelLinux

    From 4.18.0 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.97; From 6.13.0 · fixed in 6.18.40; From 6.19.0 · fixed in 7.1.5

References 8

git.kernel.org