CVE-2022-49348 [Medium] | Security Bypass in Linux Kernel

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-05	0.03%	0.07%	+0.04%
2	2025-11-21	0.06%	0.03%	-0.03%
3	2025-11-18	—	0.06%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-05

0.03%

0.07%

+0.04%

2025-11-21

0.06%

0.03%

-0.03%

2025-11-18

—

0.06%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

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

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

OS Trackers for CVE-2022-49348

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2022-49348 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2022-49348
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2022-49348
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2022-49348/
`ubuntu`	medium	CVE-2022-49348 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, ignored 150, released 114, not-affected 100, needed 42.	https://ubuntu.com/security/CVE-2022-49348

Affected software / configurations for CVE-2022-49348

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.10, < 5.10.121	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.46	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 5.17.14	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.18, < 5.18.3	cpe:2.3:o:linux:linux_kernel::::::::

References for CVE-2022-49348

URL	Tags
https://git.kernel.org/stable/c/55b4dbb29054a05d839562f6d635ce05669b016d	Patch
https://git.kernel.org/stable/c/af2f1932743fb52ebcb008ad7ac500d9df0aa796	Patch
https://git.kernel.org/stable/c/b99fd73418350dea360da8311e87a6a7b0e15a4c	Patch
https://git.kernel.org/stable/c/c878bea3c9d724ddfa05a813f30de3d25a0ba83f	Patch
https://git.kernel.org/stable/c/cc5b09cb6dacd4b32640537929ab4ee8fb2b9e04	Patch

URL

CVE-2022-49348 | ext4: filter out EXT4_FC_REPLAY from on-disk superblock field s_state

Exploit prediction scoring system (EPSS) score for CVE-2022-49348

Common vulnerability scoring system (CVSS) metrics for CVE-2022-49348

Weakness enumeration for CVE-2022-49348

OS Trackers for CVE-2022-49348

Affected software / configurations for CVE-2022-49348

References for CVE-2022-49348