CVE-2026-31431 "Copy Fail": How a 9-Year-Old Linux Kernel Bug Gives Any Local User Root in 732 Bytes
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Discussion of the blog article CVE-2026-31431 "Copy Fail": How a 9-Year-Old Linux Kernel Bug Gives Any Local User Root in 732 Bytes.
CVE-2026-31431 chains AF_ALG, splice(), and authencesn's ESN scratch write into a deterministic 4-byte page cache write that gives an unprivileged local user root. Full technical breakdown, exploit mechanics, detection, mitigation, and patch status per distro.
Discussion thread — share findings, corrections and follow-ups below.