CVE-2026-93208: Linux kernel · kasan: fix cache shrink race with CPU hotplug
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- 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.
Exploitation evidence
Disclosed: evidence found.
CVE published 24 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 for this issue has been implemented in the Linux kernel by modifying the cache shrink and destroy paths to iterate over all possible CPUs rather than only online CPUs, ensuring proper cleanup of per-CPU shrink lists. Users should apply the updated kernel versions containing this fix. Since this affects CONFIG_KASAN_GENERIC kernels, enabling this configuration and updating to a patched kernel version mitigates the issue.
Description
A race condition in the Linux kernel's KASAN quarantine cache shrink and CPU hotplug handling was fixed. The issue caused objects to remain on per-CPU shrink lists when CPUs were offlined during cache shrink operations, preventing proper release of memory slabs and causing kernel warnings during cache destruction. This was observed intermittently with the virtio-9p filesystem during mount and unmount operations. The fix ensures iteration over all possible CPUs, not just online CPUs, to properly drain these lists and prevent stale objects from remaining.
References
- ubuntu.com/security/CVE-2026-93208 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-93208 (opens in a new tab)
- git.kernel.org/stable/c/8790303cbaac52a11dfed4aab261f8ea60682525 (opens in a new tab)
- git.kernel.org/stable/c/30e8cb8598aa41b1b9f8803081d2ae5e5369c0f3 (opens in a new tab)
- git.kernel.org/stable/c/7cd164f0e1bab0f8dd125c92ed4f19bbd6b92a4a (opens in a new tab)
- git.kernel.org/stable/c/709c3646545e0a1f99a5816384c633f6552c5a98 (opens in a new tab)
- git.kernel.org/stable/c/3119d58e4ef8719d669911d38a53fc00086ac48b (opens in a new tab)