CVE-2025-38306: fs/fhandle.c: fix a race in call of has_locked_children()

Severity: medium (CVSS 4.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-10 · updated 2026-07-30
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: fs/fhandle.c: fix a race in call of has_locked_children() may_decode_fh() is calling has_locked_children() while holding no locks. That's an oopsable race... The rest of the callers are safe since they are holding namespace_sem and are guaranteed a positive refcount on the mount in question. Rename the current has_locked_children() to __has_locked_children(), make it static and switch the fs/namespace.c users to it. Make has_locked_children() a wrapper for __has_locked_children(), calling the latter under read_seqlock_excl(&mount_lock).

Affected products

Linux kernel: from 6.11 before 6.12.46; from 6.13 before 6.15.3 — fixed in 6.12.46, 6.15.3

How to fix

Upgrade to a fixed version: Linux kernel 6.12.46, 6.15.3. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-38306 or the next vulnerability affects your stack