CVE-2026-90326: Linux kernel · blk-cgroup: fix race between policy activation and blkg destruction
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 race condition by extending mutex coverage to synchronize policy activation rollback and block group destruction. Users should apply the official kernel updates that include this fix. Since this is a kernel-level vulnerability, upgrading to a patched kernel version is the recommended remediation. No alternative mitigations are indicated in the advisory.
Description
A race condition vulnerability in the Linux kernel's block cgroup (blk-cgroup) subsystem has been resolved. The flaw involves a race between policy activation and block group (blkg) destruction during IO scheduler switching, leading to use-after-free and memory leak issues. This occurs when blkcg_activate_policy() allocates policy data for block groups but races with concurrent block cgroup deletion, causing access to freed memory. The issue affects specific Linux kernel versions used in various Ubuntu releases.
References
- nvd.nist.gov/vuln/detail/CVE-2026-90326 (opens in a new tab)
- git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df (opens in a new tab)
- git.kernel.org/stable/c/2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd (opens in a new tab)
- git.kernel.org/stable/c/5313d4d41739b0cb63000747c97bb1217ac45f3e (opens in a new tab)
- git.kernel.org/stable/c/ac34e655dffa74349d885a43d098115336f53842 (opens in a new tab)
- git.kernel.org/stable/c/b5dae1cd0d8368b4338430ff93403df67f0b8bcc (opens in a new tab)
- ubuntu.com/security/CVE-2026-90326 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-90326 (opens in a new tab)
- git.kernel.org/linus/5313d4d41739b0cb63000747c97bb1217ac45f3e (opens in a new tab)