CVE-2026-53391: Linux kernel · NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 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 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +43
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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
A patch is available and should be applied by updating to the fixed linux-aws kernel versions as provided by the vendor (Ubuntu). After updating, a system reboot is required. The vendor advisory confirms the issue is resolved in these updates. No additional mitigation steps are required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's NFSv4/pNFS implementation could cause a kernel NULL pointer dereference when processing zero-length r_addr values in multipath device server addresses. This flaw is triggered by malformed GETDEVICEINFO multipath-DS bodies from malicious or compromised metadata servers, leading to a denial of service (kernel panic) on pNFS-flexfile clients. The issue has been resolved by explicitly rejecting zero-length r_addr inputs, causing the decoder to fail safely. The vulnerability affects specific linux-aws kernel versions and has a CVSS score of 7.5.
References
- nvd.nist.gov/vuln/detail/CVE-2026-53391 (opens in a new tab)
- git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956 (opens in a new tab)
- git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182 (opens in a new tab)
- git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25 (opens in a new tab)
- git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e (opens in a new tab)
- git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea (opens in a new tab)
- git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9 (opens in a new tab)
- git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d (opens in a new tab)
- ubuntu.com/security/CVE-2026-53391 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53391 (opens in a new tab)
- git.kernel.org/linus/41fe0f7b84f0cb822ae10ab08592996a592b2a25 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-53391.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)