CVE-2026-63810: Linux kernel · block: Avoid mounting the bdev pseudo-filesystem in userspace
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, 12:55 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% 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 19 Jul 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 update the Linux kernel to a fixed version. The vendor advisory from Ubuntu confirms that this and other kernel vulnerabilities have been fixed in recent kernel releases. Users should upgrade to the patched kernel versions as per their distribution's security notices.
Description
A vulnerability in the Linux kernel's block subsystem related to the bdev pseudo-filesystem has been resolved. The bdev pseudo-filesystem is an internal kernel filesystem that should not be mounted by userspace. The flaw allowed userspace to attempt mounting it, leading to a kernel NULL pointer dereference due to invalid inode operations pointers. This issue was identified and fixed by unregistering the bdev pseudo-filesystem to prevent mounting attempts.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63810 (opens in a new tab)
- git.kernel.org/stable/c/197971e6ffc0a6356b2ba2b22beb42bc0f7e412d (opens in a new tab)
- git.kernel.org/stable/c/3804e6de30ae7b053d53341d9d6944356cf23b40 (opens in a new tab)
- git.kernel.org/stable/c/717f721eb67d2dacd3ed5f7495aef2f442e84ce4 (opens in a new tab)
- git.kernel.org/stable/c/f73aa66dffcb8e61e78f01b56163ec16a15d06d2 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63810 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63810 (opens in a new tab)
- git.kernel.org/linus/f73aa66dffcb8e61e78f01b56163ec16a15d06d2 (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)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- git.kernel.org/stable/c/1a02a5028bd6dead1f8503854ef3168d651cd417 (opens in a new tab)
- git.kernel.org/stable/c/3d3fcf23993bb756de2f912ab631cfdcc4746554 (opens in a new tab)
- git.kernel.org/stable/c/99cde0a7b1e98fd3970aabef1300918e91698dd5 (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-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)