CVE-2022-49348: In the Linux kernel, the following vulnerability has been resolved: ext4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state The EXT4_F...

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state The EXT4_FC_REPLAY bit in sbi->s_mount_state is used to indicate that we are in the middle of replay the fast commit journal. This was actually a mistake, since the sbi->s_mount_info is initialized from es->s_state. Arguably s_mount_state is misleadingly named, but the name is historical --- s_mount_state and s_state dates back to ext2. What should have been used is the ext4_{set,clear,test}_mount_flag() inline functions, which sets EXT4_MF_* bits in sbi->s_mount_flags. The problem with using EXT4_FC_REPLAY is that a maliciously corrupted superblock could result in EXT4_FC_REPLAY getting set in s_mount_state. This bypasses some sanity checks, and this can trigger a BUG() in ext4_es_cache_extent(). As a easy-to-backport-fix, filter out the EXT4_FC_REPLAY bit for now. We should eventually transition away from EXT4_FC_REPLAY to something like EXT4_MF_REPLAY.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.26%

17.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 5.10, < 5.10.121
Linux	Linux Kernel	>= 5.11, < 5.15.46
Linux	Linux Kernel	>= 5.16, < 5.17.14
Linux	Linux Kernel	>= 5.18, < 5.18.3

References

Timeline

Published: Feb 26, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2022-49348?

In the Linux kernel, the following vulnerability has been resolved: ext4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state The EXT4_FC_REPLAY bit in sbi->s_mount_state is used to indicate that we are in the middle of replay the fast commit journal. This was actually a mistake, since the sbi->s_mount_info is initialized from es->s_state. Arguably s_mount_state is misleadingly named, but the name is historical --- s_mount_state and s_state dates back to ext2. What should have been used is the ext4_{set,clear,test}_mount_flag() inline functions, which sets EXT4_MF_* bits in sbi->s_mount_flags. The problem with using EXT4_FC_REPLAY is that a maliciously corrupted superblock could result in EXT4_FC_REPLAY getting set in s_mount_state. This bypasses some sanity checks, and this can trigger a BUG() in ext4_es_cache_extent(). As a easy-to-backport-fix, filter out the EXT4_FC_REPLAY bit for now. We should eventually transition away from EXT4_FC_REPLAY to something like EXT4_MF_REPLAY.

How severe is CVE-2022-49348?

CVE-2022-49348 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2022-49348?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.