CVE-2023-54099

What it is

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/[email protected]/T/

At a glance

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2025-12-24 13:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:46 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: not scored yet.
• Fix: none linked yet, which raises it.

Details

Published

2025-12-24 13:16 UTC

Last modified

2026-06-17 06:46 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Deferred

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2023-54099.md and follow it. Check whether this project is affected by CVE-2023-54099. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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