CVE-2022-50344

MEDIUM EPSS 4.5%
Published Sep 16, 20259mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Sep 16, 2025 9mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix null-ptr-deref in ext4_write_info I caught a null-ptr-deref bug as follows: ================================================================== KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339 RIP: 0010:ext4_write_info+0x53/0x1b0 [...] Call Trace: dquot_writeback_dquots+0x341/0x9a0 ext4_sync_fs+0x19e/0x800 __sync_filesystem+0x83/0x100 sync_filesystem+0x89/0xf0 generic_shutdown_super+0x79/0x3e0 kill_block_super+0xa1/0x110 deactivate_locked_super+0xac/0x130 deactivate_super+0xb6/0xd0 cleanup_mnt+0x289/0x400 __cleanup_mnt+0x16/0x20 task_work_run+0x11c/0x1c0 exit_to_user_mode_prepare+0x203/0x210 syscall_exit_to_user_mode+0x5b/0x3a0 do_syscall_64+0x59/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ================================================================== Above issue may happen as follows: ------------------------------------- exit_to_user_mode_prepare task_work_run __cleanup_mnt cleanup_mnt deactivate_super deactivate_locked_super kill_block_super generic_shutdown_super shrink_dcache_for_umount dentry = sb->s_root sb->s_root = NULL <--- Here set NULL sync_filesystem __sync_filesystem sb->s_op->sync_fs > ext4_sync_fs dquot_writeback_dquots sb->dq_op->write_info > ext4_write_info ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2) d_inode(sb->s_root) s_root->d_inode <--- Null pointer dereference To solve this problem, we use ext4_journal_start_sb directly to avoid s_root being used.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
4.5% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 8

VendorProductVersionRange
linuxlinux_kernel* <4.9.331
linuxlinux_kernel*≥4.10  –  <4.14.296
linuxlinux_kernel*≥4.15  –  <4.19.262
linuxlinux_kernel*≥4.20  –  <5.4.220
linuxlinux_kernel*≥5.5  –  <5.10.150
linuxlinux_kernel*≥5.11  –  <5.15.75
linuxlinux_kernel*≥5.16  –  <5.19.17
linuxlinux_kernel*≥6.0  –  <6.0.3

References 9

  • git.kernel.org https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60
    Patch