CVE-2026-31400: Linux kernel · sunrpc: fix cache_request leak in cache_release
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · patch available : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
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 3 Apr 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official fix is available and should be applied. The vulnerability has been resolved in updated Linux kernel versions as indicated by the vendor advisory. Users should update to patched kernel versions to remediate this issue.
Description
A memory management flaw in the Linux kernel's sunrpc subsystem caused a cache_request object to leak when a reader's file descriptor was closed mid-read. The issue arises because cache_release() decrements the readers count but does not free the request when appropriate, leading to resource leakage. This vulnerability has been fixed by adding cleanup logic to cache_release() to free the cache_request when readers drop to zero and CACHE_PENDING is clear.
References
- ubuntu.com/security/CVE-2026-31400 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-31400 (opens in a new tab)
- git.kernel.org/linus/17ad31b3a43b72aec3a3d83605891e1397d0d065 (opens in a new tab)
- git.kernel.org/stable/c/17ad31b3a43b72aec3a3d83605891e1397d0d065 (opens in a new tab)
- git.kernel.org/stable/c/301670dcd098c1fe5c2fe90fb3c7a8f4814d2351 (opens in a new tab)
- git.kernel.org/stable/c/373457de14281c1fc7cace6fc4c8a267fc176673 (opens in a new tab)
- git.kernel.org/stable/c/41f6ba6c98a618043d2cd71030bf9a752dfab8b2 (opens in a new tab)
- git.kernel.org/stable/c/7bcd5e318876ac638c8ceade7a648e76ac8c48e1 (opens in a new tab)
- git.kernel.org/stable/c/be5c35960e5ead70862736161836e2d1bc7352dc (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8597-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)