PT-2026-54809 · Linux · Linux Kernel
Published
2026-07-01
·
Updated
2026-07-04
·
CVE-2026-53341
None
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Name of the Vulnerable Software and Affected Versions
Linux kernel (affected versions not specified)
Description
A Use-After-Free (UAF) issue exists in the
may decode fh() function. The function accesses mount::mnt ns without holding necessary locks, allowing a mount to be concurrently unmounted and the mnt namespace to be freed after an RCU (Read-Copy-Update) grace period. This race condition occurs when a mount point is created using open tree(..., OPEN TREE CLONE). The issue is only reachable if CONFIG PREEMPTION or CONFIG RCU STRICT GRACE PERIOD is enabled. Potential impacts include kernel crashes due to invalid address dereferencing, endless loops, or the leaking of integer comparison results to userspace via the cap capable() level check.Recommendations
Apply the fix that implements
rcu read lock() around the mount::mnt ns access in the may decode fh() function.
Use WRITE ONCE() for writers that may race with lockless readers.
As a temporary mitigation, ensure that CONFIG PREEMPTION and CONFIG RCU STRICT GRACE PERIOD are disabled if the environment allows.Exploit
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Related Identifiers
Affected Products
Linux Kernel