CVE-2025-40139: Linux kernel · smc: Use __sk_dst_get() and dst_dev_rcu() in in smc_clc_prfx_set().
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% 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 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
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel by modifying smc_clc_prfx_set() to use __sk_dst_get() and dst_dev_rcu() under RCU read lock. Users should apply the official kernel updates containing this patch when available.
Description
A use-after-free (UAF) vulnerability in the Linux kernel's smc_clc_prfx_set() function was resolved by changing how socket destination device references are accessed. The flaw involved unsafe use of sk_dst_get(sk)->dev without proper synchronization, which could lead to memory corruption. The fix uses __sk_dst_get() and dst_dev_rcu() under RCU read lock to prevent UAF. This vulnerability affects local attackers with low privileges and can result in high impact on confidentiality, integrity, and availability.
References
- nvd.nist.gov/vuln/detail/CVE-2025-40139 (opens in a new tab)
- git.kernel.org/stable/c/0736993bfe5c7a9c744ae3fac62d769dfdae54e1 (opens in a new tab)
- git.kernel.org/stable/c/935d783e5de9b64587f3adb25641dd8385e64ddb (opens in a new tab)
- git.kernel.org/stable/c/5a2fccc4b32c13ddde3676f9e15e1a9baa7d6fde (opens in a new tab)
- git.kernel.org/stable/c/80d1fd39f4e37d836655e9f7ffccaf78925049bf (opens in a new tab)
- git.kernel.org/stable/c/956c57daba55cf9ed25d9f2512883b8a1a927599 (opens in a new tab)