CVE-2026-90149: Linux kernel · NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 49% 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:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 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 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 fix has been implemented in the Linux kernel to address this issue by adding proper NULL checks and fallback mechanisms in the NFSv4.0 flexfiles code paths. Users should apply the updated Linux Azure kernel versions that include this fix. Patch status is confirmed by the presence of fixed versions listed in the affectedVersions field.
Description
A NULL pointer dereference vulnerability in the Linux kernel's NFSv4.0 flexfiles data server implementation could cause kernel crashes (oops) during I/O operations. This occurs because the code incorrectly assumes the presence of a session for NFSv4.0 clients, which do not have sessions, leading to dereferencing a NULL pointer. The issue affects multiple specific Linux Azure kernel versions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-90149 (opens in a new tab)
- git.kernel.org/stable/c/163c16e01f53fc8eb8d0f3484ae6c382265ecbbd (opens in a new tab)
- git.kernel.org/stable/c/2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc (opens in a new tab)
- git.kernel.org/stable/c/436a214514e24103159aea455147d58b44a8a585 (opens in a new tab)
- ubuntu.com/security/CVE-2026-90149 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-90149 (opens in a new tab)
- git.kernel.org/linus/2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc (opens in a new tab)