{"id":"CVE-2026-31525","title":"bpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN\n\nThe BPF interpreter's signed 32-bit division and modulo handlers use\nthe kernel abs() macro on s32 ope…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < 694ea55f1b1c74f9942d91ec366ae9e822422e42","Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < 9ab1227765c446942f290c83382f0b19887c55cf","Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < f14ca604c0ff274fba19f73f1f0485c0047c1396","Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < 0d5d8c3ce45c734aaf3c51cbef59155a6746157d","Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < c77b30bd1dcb61f66c640ff7d2757816210c7cb0","Linux 6.6"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:10:36.308610Z"},"exploitAvailable":true,"published":"2026-04-22","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:14.562Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31525","references":[{"url":"https://git.kernel.org/stable/c/694ea55f1b1c74f9942d91ec366ae9e822422e42"},{"url":"https://git.kernel.org/stable/c/9ab1227765c446942f290c83382f0b19887c55cf"},{"url":"https://git.kernel.org/stable/c/f14ca604c0ff274fba19f73f1f0485c0047c1396"},{"url":"https://git.kernel.org/stable/c/0d5d8c3ce45c734aaf3c51cbef59155a6746157d"},{"url":"https://git.kernel.org/stable/c/c77b30bd1dcb61f66c640ff7d2757816210c7cb0"}],"tags":["cve.org","exploit-available"],"epss":0.00175,"epssPercentile":0.06549,"exploits":{"github":1,"githubRepos":["https://github.com/HORKimhab/CVE-2026-31525"],"checkedAt":"2026-10-16T17:25:21.010Z"},"ingestedAt":"2026-10-16T17:24:46.659Z","slug":"CVE-2026-31525","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN\n\nThe BPF interpreter's signed 32-bit division and modulo handlers use\nthe kernel abs() macro on s32 operands. The abs() macro documentation\n(include/linux/math.h) explicitly states the result is undefined when\nthe input is the type minimum. When DST contains S32_MIN (0x80000000),\nabs((s32)DST) triggers undefined behavior and returns S32_MIN unchanged\non arm64/x86. This value is then sign-extended to u64 as\n0xFFFFFFFF80000000, causing do_div() to compute the wrong result.\n\nThe verifier's abstract interpretation (scalar32_min_max_sdiv) computes\nthe mathematically correct result for range tracking, creating a\nverifier/interpreter mismatch that can be exploited for out-of-bounds\nmap value access.\n\nIntroduce abs_s32() which handles S32_MIN correctly by casting to u32\nbefore negating, avoiding signed overflow entirely. Replace all 8\nabs((s32)...) call sites in the interpreter's sdiv32/smod32 handlers.\n\ns32 is the only affected case -- the s64 division/modulo handlers do\nnot use abs().\n\n## Affected\n\n- `Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < 694ea55f1b1c74f9942d91ec366ae9e822422e42`\n- `Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < 9ab1227765c446942f290c83382f0b19887c55cf`\n- `Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < f14ca604c0ff274fba19f73f1f0485c0047c1396`\n- `Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < 0d5d8c3ce45c734aaf3c51cbef59155a6746157d`\n- `Linux >= ec0e2da95f72d4a46050a4d994e4fe471474fd80 < c77b30bd1dcb61f66c640ff7d2757816210c7cb0`\n- `Linux 6.6`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[]}