CVE-2022-50344

ext4: fix null-ptr-deref in ext4_write_info

Severity Score

5.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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.

This update provides the initial livepatch for this kernel update. This update does not contain any fixes and will be updated with livepatches later.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2025-09-16 CVE Reserved
2025-09-16 CVE Published
2026-01-14 CVE Updated
2026-02-24 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-476: NULL Pointer Dereference

CAPEC

References (12)

URL	Tag	Source
https://git.kernel.org/stable/c/a1177825719ccef3f76ef39bbfd5ebb6087d53c7	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435	2022-10-26
https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b	2022-10-26
https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3	2022-10-26
https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4	2022-10-26
https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d	2022-10-26
https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7	2022-10-26
https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1	2022-10-24
https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888	2022-10-21
https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60	2022-09-29

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2022-50344	2024-05-22
https://bugzilla.redhat.com/show_bug.cgi?id=2395860	2024-05-22

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 4.9.331 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 4.9.331"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 4.14.296 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 4.14.296"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 4.19.262 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 4.19.262"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 5.4.220 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 5.4.220"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 5.10.150 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 5.10.150"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 5.15.75 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 5.15.75"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 5.19.17 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 5.19.17"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 6.0.3 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 6.0.3"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.6 < 6.1 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.6 < 6.1"		en		Affected