GHSA-XXR8-HFWW-QGF6
Vulnerability from github – Published: 2026-07-19 12:30 – Updated: 2026-07-19 12:30In 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: 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.
{
"affected": [],
"aliases": [
"CVE-2026-63810"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T12:16:53Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: Avoid mounting the bdev pseudo-filesystem in userspace\n\nThe bdev pseudo-filesystem is an internal kernel filesystem with which\nuserspace should not interfere. Unregister it so that userspace cannot\neven attempt to mount it.\n\nThis fixes a bug [1] that occurs when attempting to access files,\nbecause the system call move_mount() uses pointers declared in the\ninode_operations structure, which for the bdev pseudo-filesystem\nare always equal to 0. `inode-\u003ei_op = \u0026empty_iops;`\n\n[1]\n\n BUG: kernel NULL pointer dereference, address: 0000000000000000\n #PF: supervisor instruction fetch in kernel mode\n #PF: error_code(0x0010) - not-present page\n PGD 23380067 P4D 23380067 PUD 23381067 PMD 0\n Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI\n CPU: 2 PID: 17125 Comm: syz-executor.0 Not tainted 6.1.155-syzkaller-00350-g84221fde2681 #0\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014\n RIP: 0010:0x0\n\n Call Trace:\n \u003cTASK\u003e\n lookup_open.isra.0+0x700/0x1180 fs/namei.c:3460\n open_last_lookups fs/namei.c:3550 [inline]\n path_openat+0x953/0x2700 fs/namei.c:3780\n do_filp_open+0x1c5/0x410 fs/namei.c:3810\n do_sys_openat2+0x171/0x4d0 fs/open.c:1318\n do_sys_open fs/open.c:1334 [inline]\n __do_sys_openat fs/open.c:1350 [inline]\n __se_sys_openat fs/open.c:1345 [inline]\n __x64_sys_openat+0x13c/0x1f0 fs/open.c:1345\n do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81\n entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\nFound by Linux Verification Center (linuxtesting.org) with Syzkaller.",
"id": "GHSA-xxr8-hfww-qgf6",
"modified": "2026-07-19T12:30:23Z",
"published": "2026-07-19T12:30:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63810"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/197971e6ffc0a6356b2ba2b22beb42bc0f7e412d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3804e6de30ae7b053d53341d9d6944356cf23b40"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/717f721eb67d2dacd3ed5f7495aef2f442e84ce4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f73aa66dffcb8e61e78f01b56163ec16a15d06d2"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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