CVE-2026-64326: Linux kernel · block: skip sync_blockdev() on surprise removal in bdev_mark_dead() bdev_mark_dead()'s
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-147.147 : update Linux kernel when convenient.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-147.147, 6.8.0-1067.70, 7.0.0-1012.12~24.04.1 +28
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 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- 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-8917-1 (opens in a new tab)
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 has been applied in Linux kernel versions 6.8.0-147.147, 6.8.0-1067.70, 7.0.0-1012.12~24.04.1, 6.8.0-1071.79, 7.0.0-1014.14~24.04.1, and others as listed in the fixedVersions. Users should update to these fixed kernel versions to remediate the issue. No additional mitigation is required beyond applying the official fix.
Description
A Linux kernel vulnerability (CVE-2026-64326) involves improper handling of surprise device removal in the block device subsystem. When a block device is unexpectedly removed, the kernel incorrectly calls sync_blockdev() unconditionally, which can hang indefinitely waiting on writeback operations that cannot complete. This issue was discovered via fuzzing and affects certain Linux kernel versions prior to fixed releases. The problem is resolved by skipping sync_blockdev() on surprise removal, matching the behavior of filesystem callbacks. The vulnerability has a medium severity with no confidentiality or integrity impact but can cause denial of service by hanging kernel tasks.
References
- ubuntu.com/security/CVE-2026-64326 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64326 (opens in a new tab)
- git.kernel.org/linus/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a (opens in a new tab)
- git.kernel.org/stable/c/49f06cff50a4ccf3b7a1a662ceb892b3b21a527a (opens in a new tab)
- git.kernel.org/stable/c/9818bcae3c0ca1dde4b9a334125c46676e0a9b29 (opens in a new tab)
- git.kernel.org/stable/c/aa4c4a9315764b2b7a7182e72cc5ea87520436b4 (opens in a new tab)
- git.kernel.org/stable/c/d6998ddd507c81e3829489a6ead23f17f5acb7fe (opens in a new tab)
- git.kernel.org/stable/c/f41cf35ee2a1e31374b3f54e7579c55153506e70 (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-8917-1 (opens in a new tab)