CVE-2025-40133: Linux kernel · mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable().
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.1 High · fixed in 6.17.0-1011.11 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.17.0-1011.11, 6.17.0-1008.8~24.04.1, 6.17.0-1008.8 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 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 26 Oct 2026.
What to do
Upgrade Linux kernel to 6.17.0-1011.11, 6.17.0-1008.8~24.04.1, 6.17.0-1008.8 or 6.17.0-1007.7~24.04.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| linux-hwe-edge | Affected
| Fixed in
|
AI-suggested
A fix has been implemented in the Linux kernel by modifying mptcp_active_enable() to use __sk_dst_get() and dst_dev_rcu() for safe reference access. Users should apply the official kernel updates containing this patch once available. Patch status is not explicitly confirmed in the provided data; check the vendor or Linux kernel advisories for the exact fixed versions and update accordingly.
Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: Use __sk_dst_get() and dst_dev_rcu() in mptcp_active_enable(). mptcp_active_enable() is called from subflow_finish_connect(), which is icsk->icsk_af_ops->sk_rx_dst_set() and it's not always under RCU. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu().
References
- nvd.nist.gov/vuln/detail/CVE-2025-40133 (opens in a new tab)
- git.kernel.org/stable/c/893c49a78d9f85e4b8081b908fb7c407d018106a (opens in a new tab)
- git.kernel.org/stable/c/ad16235c9d3ef7ec17c109ff39b7504f49d17072 (opens in a new tab)
- git.kernel.org/stable/c/cc976ec9e38bb79409de3261ba1dbb6868e2a53e (opens in a new tab)
- ubuntu.com/security/CVE-2025-40133 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-40133 (opens in a new tab)
- git.kernel.org/linus/893c49a78d9f85e4b8081b908fb7c407d018106a (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8048-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-3 (opens in a new tab)