Vulnerability · CVE-2026-63810
block: Avoid mounting the bdev pseudo-filesystem in userspace
Published Jul 19, 2026 · corrected/updated Oct 15, 2026 · Linux Linux · evidence confidence high
In the Linux kernel, the following vulnerability has been resolved: block: Avoid mounting the bdev pseudo-filesystem in userspace The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even attempt to mount it. This fixes a bug [1] that occurs when attempting to access files, because the system call move_mount() uses pointers declared in the inode_operations structure, which for the bdev pseudo-filesystem are always equal to 0. [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 23380067 P4D 23380067 PUD 23381067 PMD 0 Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI CPU: 2 PID: 17125 Comm: syz-executor.0 Not tainted 6.1.155-syzkaller-00350-g84221fde2681 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:0x0 Call Trace: lookup_open.isra.0+0x700/0x1180 fs/namei.c:3460 open_last_lookups fs/namei.c:3550 [inline] path_openat+0x953/0x2700 fs/namei.c:3780 do_filp_open+0x1c5/0x410 fs/namei.c:3810 do_sys_openat2+0x171/0x4d0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x13c/0x1f0 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-63810 is a unknown public vulnerability record for Linux Linux. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether Linux Linux is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: Linux Linux. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: EPSS 0.2%. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: circl, cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Jul 19, 2026 · NIST NVD
Detected
In the Linux kernel, the following vulnerability has been resolved: block: Avoid mounting the bdev pseudo-filesystem in userspace The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even attempt to mount it. This fixes a bug [1] that occurs when attempting to access files, because the system call move_mount()
Oct 15, 2026 · NIST NVD
Updated
In the Linux kernel, the following vulnerability has been resolved: block: Avoid mounting the bdev pseudo-filesystem in userspace The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even attempt to mount it. This fixes a bug [1] that occurs when attempting to access files, because the system call move_mount()
Affected
- vendor Linux Linuxversion unspecified
Sources
- CIRCL Vulnerability LookupVulnerability recordCVE-2026-63810
In the Linux kernel, the following vulnerability has been resolved: block: Avoid mounting the bdev pseudo-filesystem in userspace The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even att
vulnerability.circl.lu - CVE.orgVulnerability recordCVE-2026-63810
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-63810
30-day exploitation probability 0.2%
first.org - NIST NVDVulnerability recordCVE-2026-63810
In the Linux kernel, the following vulnerability has been resolved: block: Avoid mounting the bdev pseudo-filesystem in userspace The bdev pseudo-filesystem is an internal kernel filesystem with which userspace should not interfere. Unregister it so that userspace cannot even a
nvd.nist.gov