block: Avoid mounting the bdev pseudo-filesystem in userspace
Summary
| CVE | CVE-2026-63810 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-19 12:16:53 UTC |
| Updated | 2026-07-19 12:16:53 UTC |
| Description | 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. `inode->i_op = &empty_iops;` [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: <TASK> 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. |
Risk And Classification
EPSS: 0.001680000 probability, percentile 0.065060000 (date 2026-07-20)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 197971e6ffc0a6356b2ba2b22beb42bc0f7e412d git | Not specified |
| CNA | Linux | Linux | affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 3804e6de30ae7b053d53341d9d6944356cf23b40 git | Not specified |
| CNA | Linux | Linux | affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 717f721eb67d2dacd3ed5f7495aef2f442e84ce4 git | Not specified |
| CNA | Linux | Linux | affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 f73aa66dffcb8e61e78f01b56163ec16a15d06d2 git | Not specified |
| CNA | Linux | Linux | affected 2.6.12 | Not specified |
| CNA | Linux | Linux | unaffected 2.6.12 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.95 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.38 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.3 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/3804e6de30ae7b053d53341d9d6944356cf23b40 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/197971e6ffc0a6356b2ba2b22beb42bc0f7e412d | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/717f721eb67d2dacd3ed5f7495aef2f442e84ce4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f73aa66dffcb8e61e78f01b56163ec16a15d06d2 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.