CVE-2025-40169: Linux

High severity, CVSS 7.8. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject negative offsets for ALU ops When verifying BPF programs, the check_alu_op() function validates instructions with ALU operations. The 'offset' field in these instructions is a signed 16-bit integer. The existing check 'insn->off > 1' was intended to ensure the offset is either 0, or 1 for BPF_MOD/BPF_DIV. However, because 'insn->off' is signed, this check incorrectly accepts all negative values (e.g., -1). This commit tightens the validation by changing the condition to '(insn->off != 0 && insn->off != 1)'. This ensures that any value other than the explicitly permitted 0 and 1 is rejected, hardening the verifier against malformed BPF programs.

Affected products

• Linux Linux: from 6.6, before 6.6.112 (fixed in 6.6.112); from 6.7, before 6.12.53 (fixed in 6.12.53); from 6.13, before 6.17.3 (fixed in 6.17.3)

Published 2025-11-12. Last modified 2026-07-30.