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VulnerabilityPublished Updated

CVE-2025-40206: Linux kernel · netfilter: nft_objref: validate objref and objrefmap expressions

Source GCVE Database

0

Not known to be exploited · CVSS 7.8 High.

Data as of 26 Oct 2026, 12:55 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 13 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

The vulnerability description indicates that validation functions have been implemented to prevent the crash, and nftables now rejects unsupported synproxy references. Users should monitor vendor advisories for official patches or updates and avoid referencing synproxy objects from the OUTPUT hook until a fix is applied.

Description

A vulnerability in the Linux kernel's netfilter nft_objref component allows referencing a synproxy stateful object from the OUTPUT hook, causing a kernel crash due to infinite recursive calls. This issue has been resolved by implementing validation functions for objref and objrefmap expressions, specifically for the NFT_OBJECT_SYNPROXY type. Attempts to reference a synproxy object in the OUTPUT hook now result in an error preventing the crash.

References

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