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🛡️ CVE-2022-49170 — kernel

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

f2fs: fix to do sanity check on curseg->alloc_type

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to do sanity check on curseg->alloc_type

As Wenqing Liu reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215657

  • Overview

UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image

  • Reproduce

tested on kernel 5.17-rc4, 5.17-rc6

1. mkdir test_crash

2. cd test_crash

3. unzip tmp2.zip

4. mkdir mnt

5. ./single_test.sh f2fs 2

  • Kernel dump

[ 46.434454] loop0: detected capacity change from 0 to 131072

[ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9

[ 46.738319] ================================================================================

[ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2

[ 46.738475] index 231 is out of range for type 'unsigned int [2]'

[ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1

[ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014

[ 46.738551] Call Trace:

[ 46.738556] <TASK>

[ 46.738563] dump_stack_lvl+0x47/0x5c

[ 46.738581] ubsan_epilogue+0x5/0x50

[ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80

[ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs]

[ 46.738819] do_write_page+0xef/0x210 [f2fs]

[ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs]

[ 46.739038] __write_node_page+0x2b7/0x920 [f2fs]

[ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs]

[ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]

[ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs]

[ 46.739507] deactivate_locked_super+0x60/0xc0

[ 46.739517] deactivate_super+0x70/0xb0

[ 46.739524] cleanup_mnt+0x11a/0x200

[ 46.739532] __cleanup_mnt+0x16/0x20

[ 46.739538] task_work_run+0x67/0xa0

[ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0

[ 46.739559] syscall_exit_to_user_mode+0x26/0x40

[ 46.739568] do_syscall_64+0x46/0xb0

[ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae

The root cause is we missed to do sanity check on curseg->alloc_type,

result in out-of-bound accessing on sbi->block_count[] array, fix it.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2022-49170 is recorded against 2 packages.

  • kernel (from 5.17.0 up to 5.17.2)
  • linux-kernel (from 5.17 up to 5.17.2)

Timeline and source

Published on 26 February 2025 and last revised on 14 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

Other advisories for this package

kernel has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2022-49170 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity High
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-02-26
Updated 2026-08-20
Modified 2026-08-14

Affected Packages

Software From version Fixed in
kernel 5.17.0 5.17.2
linux-kernel 5.17 5.17.2

Similar Threats

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