Vulnerability
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% 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:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Oct 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
Since this is a kernel-level issue, applying official Linux kernel updates that include the fix is recommended once available. Until then, avoid triggering conditions that cause af_alg_sendmsg to abort if possible.
Description
A vulnerability in the Linux kernel's crypto subsystem (af_alg) could cause a crash due to improper handling of the ctx->merge variable when af_alg_sendmsg aborts. The issue arises because ctx->merge may retain a garbage value from a previous loop iteration, leading to a crash on subsequent calls. The fix involves setting ctx->merge to zero early in the processing loop to prevent this condition.
References
- nvd.nist.gov/vuln/detail/CVE-2025-39931 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- git.kernel.org/stable/c/045ee26aa3920a47ec46d7fcb302420bf01fd753 (opens in a new tab)
- git.kernel.org/stable/c/2374c11189ef704a3e4863646369f1b8e6a27d71 (opens in a new tab)
- git.kernel.org/stable/c/24c1106504c625fabd3b7229611af617b4c27ac7 (opens in a new tab)
- git.kernel.org/stable/c/28f6f37abca7c5c9eb3959c66310f1d4d98b8aaf (opens in a new tab)
- git.kernel.org/stable/c/6241b9e2809b12da9130894cf5beddf088dc1b8a (opens in a new tab)
- git.kernel.org/stable/c/9574b2330dbd2b5459b74d3b5e9619d39299fc6f (opens in a new tab)
- git.kernel.org/stable/c/db2b42425dfbde4983b0c20fb7cfa05f70e6a745 (opens in a new tab)