seg6: validate SRH length before reading fixed fields

These records connect through source-stated identifiers. Shared identifiers or dates alone do not establish shared exposure, root cause or applicability.

CVE-2026-72400 · Microsoft / collected KEV context

cve-program · CVE-2026-72400

• https://git.kernel.org/stable/c/715eb12e453df752f1b4baaf972c3acff0ab9402
• https://git.kernel.org/stable/c/7247d05c987c3eec4bb7c2306dbd77ecdf3b7c73
• https://git.kernel.org/stable/c/071f1a38d7ddbadee29c09b9e3ee0ff3a61e6a0e
• https://git.kernel.org/stable/c/804bb969f194c93497ba632b98343794c6367fdc
• https://git.kernel.org/stable/c/0fc7069d39239978130c37ebceaec85c8948d3f1
• https://git.kernel.org/stable/c/8dba7a94a269b88e500aafc25ad567ef6a423698
• https://git.kernel.org/stable/c/c9961336aa5ff83092f23e33ee86666a9dbd1b2a
• https://git.kernel.org/stable/c/a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa

No related operational record is retained in the current change model.