5.5

CVE-2022-50344: ext4: fix null-ptr-deref in ext4_write_info

Modified
AliasesUBUNTU-CVE-2022-50344DEBIAN-CVE-2022-50344
Published 16-09-2025Last modified 11-05-2026

Vulnerability summary

CVE-2022-50344 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.16%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 9 · Related 7
RHSA-2023:2458RHSA-2024:3138SUSE-SU-2025:03613-1SUSE-SU-2025:03614-1SUSE-SU-2025:03615-1SUSE-SU-2025:03626-1

Timeline

  1. 16-09-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu120 products
  • linuxAll versions (No fix recorded) | < 4.15.0-204.215 | < 5.4.0-139.156 | < 5.15.0-60.66
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 4.15.0-1150.163 | < 5.4.0-1096.104 | < 5.15.0-1030.34
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < dc451578446afd03c0c21913993c08898a691435 | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < f4b5ff0b794aa94afac7269c494550ca2f66511b | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < 947264e00c46de19a016fd81218118c708fed2f3 | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < 3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4 | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < f34ab95162763cd7352f46df169296eec28b688d | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < 533c60a0b97cee5daab376933f486207e6680fb7 | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < 4a657319cfabd6199fd0b7b65bbebf6ded7a11c1 | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < bb420e8afc854d2a1caaa23a0c129839acfb7888 | ≥ a1177825719ccef3f76ef39bbfd5ebb6087d53c7, < f9c1f248607d5546075d3f731e7607d5571f2b60 | 3.6
  • linux_kernel< 4.9.331 | ≥ 4.10, < 4.14.296 | ≥ 4.15, < 4.19.262 | ≥ 4.20, < 5.4.220 | ≥ 5.5, < 5.10.150 | ≥ 5.11, < 5.15.75 | ≥ 5.16, < 5.19.17 | ≥ 6.0, < 6.0.3
Debian1 product
  • linux< 6.0.3-1

3 vendors · 123 products

References

13 links
Show all 13 references