In the Linux kernel, the following vulnerability has been resolved:

fs: Protect reconfiguration of sb read-write from racing writes

The reconfigure / remount code takes a lot of effort to protect
filesystem's reconfiguration code from racing writes on remounting
read-only. However during remounting read-only filesystem to read-write
mode userspace writes can start immediately once we clear SB_RDONLY
flag. This is inconvenient for example for ext4 because we need to do
some writes to the filesystem (such as preparation of quota files)
before we can take userspace writes so we are clearing SB_RDONLY flag
before we are fully ready to accept userpace writes and syzbot has found
a way to exploit this [1]. Also as far as I'm reading the code
the filesystem remount code was protected from racing writes in the
legacy mount path by the mount's MNT_READONLY flag so this is relatively
new problem. It is actually fairly easy to protect remount read-write
from racing writes using sb->s_readonly_remount flag so let's just do
that instead of having to workaround these races in the filesystem code.

[1] https://lore.kernel.org/all/00000000000006a0df05f6667499@google.com/T/
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 25 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Wed, 24 Dec 2025 13:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: fs: Protect reconfiguration of sb read-write from racing writes The reconfigure / remount code takes a lot of effort to protect filesystem's reconfiguration code from racing writes on remounting read-only. However during remounting read-only filesystem to read-write mode userspace writes can start immediately once we clear SB_RDONLY flag. This is inconvenient for example for ext4 because we need to do some writes to the filesystem (such as preparation of quota files) before we can take userspace writes so we are clearing SB_RDONLY flag before we are fully ready to accept userpace writes and syzbot has found a way to exploit this [1]. Also as far as I'm reading the code the filesystem remount code was protected from racing writes in the legacy mount path by the mount's MNT_READONLY flag so this is relatively new problem. It is actually fairly easy to protect remount read-write from racing writes using sb->s_readonly_remount flag so let's just do that instead of having to workaround these races in the filesystem code. [1] https://lore.kernel.org/all/00000000000006a0df05f6667499@google.com/T/
Title fs: Protect reconfiguration of sb read-write from racing writes
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-24T13:06:25.895Z

Reserved: 2025-12-24T13:02:52.517Z

Link: CVE-2023-54099

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-12-24T13:16:11.787

Modified: 2025-12-24T13:16:11.787

Link: CVE-2023-54099

cve-icon Redhat

Severity : Low

Publid Date: 2025-12-24T00:00:00Z

Links: CVE-2023-54099 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.