CVE-2025-68775: Linux kernel · net/handshake: duplicate handshake cancellations leak socket When a handshake
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 07:57 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Jan 2026
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 2026-10-26.
What to do
AI-suggested
The vulnerability description states it has been resolved by adding a test_and_set_bit for the HANDSHAKE_F_REQ_COMPLETED flag to detect duplicate cancellations. Security teams should monitor for official Linux kernel updates addressing CVE-2025-68775 and apply them promptly once available.
Description
A critical vulnerability in the Linux kernel's network handshake code allows duplicate handshake cancellations to leak socket references, leading to a reference count underflow. This occurs when a handshake request is cancelled multiple times but not properly marked as completed, causing improper socket reference handling. The issue can arise in scenarios such as SUNRPC client-server TLS handshake timeouts. The vulnerability has been resolved by adding a mechanism to detect and handle duplicate cancellations correctly.
References
- nvd.nist.gov/vuln/detail/CVE-2025-68775 (opens in a new tab)
- git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663 (opens in a new tab)
- git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f (opens in a new tab)
- git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be (opens in a new tab)
- git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659 (opens in a new tab)