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VulnerabilityPublished Updated

CVE-2025-40169: Linux kernel · bpf: Reject negative offsets for ALU ops

Source GCVE Database

0

Not known to be exploited · CVSS 7.8 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Nov 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

AI-suggested

A fix has been implemented in the Linux kernel to correct the offset validation logic in the BPF verifier. Users should update their Linux kernel to a version that includes this fix. Since this is a kernel vulnerability, patching the kernel is the recommended remediation. No alternative mitigations are indicated.

Description

A vulnerability in the Linux kernel's BPF verifier allowed negative offsets in ALU operation instructions due to improper validation of the signed 16-bit offset field. This flaw permitted malformed BPF programs with offsets other than the explicitly allowed 0 or 1, potentially leading to high impact on confidentiality, integrity, and availability. The issue has been resolved by tightening the validation logic to reject any offset values other than 0 and 1.

References

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