CVE-2026-63978: Linux kernel · net/handshake: Drain pending requests at net namespace exit
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in ee4b2ba9d30155f9945811cd3c0c1b06d45787a9 : patch Linux kernel as a priority.
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 ee4b2ba9d30155f9945811cd3c0c1b06d45787a9, ea5fe6a73ca57e5150b8a38b341aef2636eb72f0, 9ec20c9a5a04f2c3f1cf65d21f886d7aaa6189cd +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
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available that corrects the list_splice_init() argument order and adds synchronization to prevent race conditions during draining and cancellation of handshake requests. Users should apply the official Linux kernel patch that addresses CVE-2026-63978.
Description
A critical vulnerability in the Linux kernel's network handshake code was resolved. The flaw involved incorrect handling of pending handshake requests during network namespace exit, causing requests to remain unprocessed and potentially leading to resource leaks and list corruption. The fix corrected the direction of a list splice operation and added synchronization to prevent race conditions during request cancellation and draining.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63978 (opens in a new tab)
- git.kernel.org/stable/c/8c35539db0ab0bfa1ea44efab00b053261a69469 (opens in a new tab)
- git.kernel.org/stable/c/9ec20c9a5a04f2c3f1cf65d21f886d7aaa6189cd (opens in a new tab)
- git.kernel.org/stable/c/ea5fe6a73ca57e5150b8a38b341aef2636eb72f0 (opens in a new tab)
- git.kernel.org/stable/c/2bf24a7e190aae0ea47c78099938ae056c622e44 (opens in a new tab)
- git.kernel.org/stable/c/ee4b2ba9d30155f9945811cd3c0c1b06d45787a9 (opens in a new tab)