CVE-2025-40206: Linux kernel · netfilter: nft_objref: validate objref and objrefmap expressions Referencing a
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 25 Oct 2026, 19:02 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 2026-10-25.
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
- nvd.nist.gov/vuln/detail/CVE-2025-40206 (opens in a new tab)
- git.kernel.org/stable/c/0028e0134c64d9ed21728341a74fcfc59cd0f944 (opens in a new tab)
- git.kernel.org/stable/c/4c1cf72ec10be5a9ad264650cadffa1fbce6fabd (opens in a new tab)
- git.kernel.org/stable/c/7ea55a44493a5a36c3b3293b88bbe4841f9dbaf0 (opens in a new tab)
- git.kernel.org/stable/c/f359b809d54c6e3dd1d039b97e0b68390b0e53e4 (opens in a new tab)