{"id":"CVE-2026-63810","title":"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","summary":"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. Un…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3d3fcf23993bb756de2f912ab631cfdcc4746554","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 99cde0a7b1e98fd3970aabef1300918e91698dd5","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1a02a5028bd6dead1f8503854ef3168d651cd417","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 197971e6ffc0a6356b2ba2b22beb42bc0f7e412d","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3804e6de30ae7b053d53341d9d6944356cf23b40","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 717f721eb67d2dacd3ed5f7495aef2f442e84ce4","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f73aa66dffcb8e61e78f01b56163ec16a15d06d2","Linux 2.6.12"],"published":"2026-07-19","updated":"2026-09-08","sourceUpdated":"2026-09-08T09:18:17.710","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63810","references":[{"url":"https://git.kernel.org/stable/c/197971e6ffc0a6356b2ba2b22beb42bc0f7e412d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1a02a5028bd6dead1f8503854ef3168d651cd417","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3804e6de30ae7b053d53341d9d6944356cf23b40","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3d3fcf23993bb756de2f912ab631cfdcc4746554","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/717f721eb67d2dacd3ed5f7495aef2f442e84ce4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/99cde0a7b1e98fd3970aabef1300918e91698dd5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f73aa66dffcb8e61e78f01b56163ec16a15d06d2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00187,"epssPercentile":0.07343,"ingestedAt":"2026-07-20T09:37:17.847Z","slug":"CVE-2026-63810","body":"## Overview\n\nIn 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->i_op = &empty_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 <TASK>\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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}