CVE-2026-63979: Linux kernel · net/handshake: hand off the pinned file reference to accept_doit
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in f4251190e58b209999c1ba9e6d2976136a1be055 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in f4251190e58b209999c1ba9e6d2976136a1be055, c06876d4fac38f35820946ee3b1be7d7da799cd4, b869e3e4ce1996df23b3efdbbe9a64c4ab81d745 +2
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 19 Jul 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
The description indicates the vulnerability has been resolved in the Linux kernel source code. Users should monitor official Linux kernel advisories and update to a fixed kernel version once available. No specific workaround or temporary fix is described.
Description
A critical vulnerability in the Linux kernel involving improper handling of pinned file references during network handshake operations has been resolved. The flaw allowed a race condition where the accept-side code could dereference a NULL or freed socket file pointer, potentially leading to memory corruption. The fix involves handing off an additional file reference under lock to ensure safe access during the accept operation.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63979 (opens in a new tab)
- git.kernel.org/stable/c/c06876d4fac38f35820946ee3b1be7d7da799cd4 (opens in a new tab)
- git.kernel.org/stable/c/f4251190e58b209999c1ba9e6d2976136a1be055 (opens in a new tab)
- git.kernel.org/stable/c/68eba6519cbd6359fb554a9720f3a3b6b2eba23f (opens in a new tab)