CVE-2026-64593: Linux kernel · btrfs: do not trim a device which is not writeable
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
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 5% 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
Exploitation evidence
Disclosed: evidence found.
CVE published 6 Aug 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 to affected Linux kernel versions. The vendor advisory from Ubuntu confirms that this issue has been fixed in updated kernel packages. Users should update their Linux kernel to the fixed versions to prevent this NULL pointer dereference and associated crashes.
Description
A vulnerability in the Linux kernel's Btrfs filesystem code could cause a NULL pointer dereference when trimming a device that is not writable. This occurs due to a desynchronization between device state flags and the device block pointer, leading to a kernel crash. The issue arises when a missing device is rescanned and its missing flag is cleared without updating the writable flag or device pointer. A fix has been implemented to address this condition.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64593 (opens in a new tab)
- git.kernel.org/stable/c/02c903fc6fc7e16c5d1f22d18784f1208acf43e3 (opens in a new tab)
- git.kernel.org/stable/c/1b1937eb08f51319bf71575484cde2b8c517aedc (opens in a new tab)
- git.kernel.org/stable/c/210af872eafa0cf572a84cb303c0f9d2914c1226 (opens in a new tab)
- git.kernel.org/stable/c/3d8fa4b828a86b33c60858e58aaab6df273ede05 (opens in a new tab)
- git.kernel.org/stable/c/7a64521802997257b144e6edfb4e278dbeb972dd (opens in a new tab)
- git.kernel.org/stable/c/9c894159c5b8adc84072e3af0e55b0473a69564e (opens in a new tab)
- git.kernel.org/stable/c/b4af31b898a948e29861cb0bae734058f9a49d9b (opens in a new tab)
- git.kernel.org/stable/c/f41ae7e6664f3c4361129728f2c4d5f3ed995251 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64593 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64593 (opens in a new tab)
- git.kernel.org/linus/1b1937eb08f51319bf71575484cde2b8c517aedc (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)