In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset() Patch series "nilfs2: fix UBSAN shift-out-of-bounds warnings on mount time". The first patch fixes a bug reported by syzbot, and the second one fixes the remaining bug of the same kind. Although they are triggered by the same super block data anomaly, I divided it into the above two because the details of the issues and how to fix it are different. Both are required to eliminate the shift-out-of-bounds issues at mount time. This patch (of 2): If the block size exponent information written in an on-disk superblock is corrupted, nilfs_sb2_bad_offset helper function can trigger shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn is set): shift exponent 38983 is too large for 64-bit type 'unsigned long long' Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:151 [inline] __ubsan_handle_shift_out_of_bounds+0x33d/0x3b0 lib/ubsan.c:322 nilfs_sb2_bad_offset fs/nilfs2/the_nilfs.c:449 [inline] nilfs_load_super_block+0xdf5/0xe00 fs/nilfs2/the_nilfs.c:523 init_nilfs+0xb7/0x7d0 fs/nilfs2/the_nilfs.c:577 nilfs_fill_super+0xb1/0x5d0 fs/nilfs2/super.c:1047 nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317 ... In addition, since nilfs_sb2_bad_offset() performs multiplication without considering the upper bound, the computation may overflow if the disk layout parameters are not normal. This fixes these issues by inserting preliminary sanity checks for those parameters and by converting the comparison from one involving multiplication and left bit-shifting to one using division and right bit-shifting.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

References
Link Providers
https://git.kernel.org/stable/c/1012ff77284e3bec0ec0a35a820b03ec43dec2cc cve-icon cve-icon
https://git.kernel.org/stable/c/610a2a3d7d8be3537458a378ec69396a76c385b6 cve-icon cve-icon
https://git.kernel.org/stable/c/62d11ec205ef14d8acf172cfc9904fdbf200025a cve-icon cve-icon
https://git.kernel.org/stable/c/6b0ea3df56cccd53398d0289f399f19d43136b2e cve-icon cve-icon
https://git.kernel.org/stable/c/9b3ba54025357440d6c4414c670984f628c6f6bf cve-icon cve-icon
https://git.kernel.org/stable/c/a6f89b10042baca218c8598d6db5a44c7e32625f cve-icon cve-icon
https://git.kernel.org/stable/c/b47f5c579c8186f7f5ab5e4254e0734ea5b7bf7a cve-icon cve-icon
https://git.kernel.org/stable/c/d464b035c0613856d012cf1704879d3ff3f057fb cve-icon cve-icon
https://git.kernel.org/stable/c/d706485dffbbbf848e681edda29c7a46ac55698c cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025100438-CVE-2022-50478-81f8@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2022-50478 cve-icon
https://www.cve.org/CVERecord?id=CVE-2022-50478 cve-icon
History

Mon, 06 Oct 2025 22:45:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Mon, 06 Oct 2025 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Sat, 04 Oct 2025 15:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset() Patch series "nilfs2: fix UBSAN shift-out-of-bounds warnings on mount time". The first patch fixes a bug reported by syzbot, and the second one fixes the remaining bug of the same kind. Although they are triggered by the same super block data anomaly, I divided it into the above two because the details of the issues and how to fix it are different. Both are required to eliminate the shift-out-of-bounds issues at mount time. This patch (of 2): If the block size exponent information written in an on-disk superblock is corrupted, nilfs_sb2_bad_offset helper function can trigger shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn is set): shift exponent 38983 is too large for 64-bit type 'unsigned long long' Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:151 [inline] __ubsan_handle_shift_out_of_bounds+0x33d/0x3b0 lib/ubsan.c:322 nilfs_sb2_bad_offset fs/nilfs2/the_nilfs.c:449 [inline] nilfs_load_super_block+0xdf5/0xe00 fs/nilfs2/the_nilfs.c:523 init_nilfs+0xb7/0x7d0 fs/nilfs2/the_nilfs.c:577 nilfs_fill_super+0xb1/0x5d0 fs/nilfs2/super.c:1047 nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317 ... In addition, since nilfs_sb2_bad_offset() performs multiplication without considering the upper bound, the computation may overflow if the disk layout parameters are not normal. This fixes these issues by inserting preliminary sanity checks for those parameters and by converting the comparison from one involving multiplication and left bit-shifting to one using division and right bit-shifting.
Title nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset()
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-10-04T15:16:38.346Z

Reserved: 2025-10-04T15:13:33.467Z

Link: CVE-2022-50478

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-10-04T16:15:44.417

Modified: 2025-10-06T14:56:47.823

Link: CVE-2022-50478

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-10-04T00:00:00Z

Links: CVE-2022-50478 - Bugzilla