Vulnerability in Linux

CVE-2025-40169

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.001 (3.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-40169: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000

Affected products

  • Linux — versions ec0e2da95f72d4a46050a4d994e4fe471474fd80, 6.6, 0

References

Frequently asked questions

What is CVE-2025-40169?
CVE-2025-40169 is a high-severity vulnerability in Linux. CVSS score: 7.8/10. Published 2025-11-12.
How severe is CVE-2025-40169?
High severity. CVSS v3 base score is 7.8 out of 10.