PT-2025-9000 · Linux+3 · Linux Kernel+3

Published

2025-01-23

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Updated

2026-04-20

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CVE-2025-21809

CVSS v3.1

5.5

Medium

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 6.13.0-rc5-build2+ #1223
Description A vulnerability in the Linux kernel has been identified, related to the rxrpc and afs modules. The issue arises from the use of spinlocks in the rxnet->peer hash lock, which can lead to a deadlock when the RCU cleanup is called from a BH context. This can occur when an rxrpc peer object runs out of references and is removed from the peer hash table, requiring the taking of a spinlock. The possibility of deadlock exists if the BH-based RCU cleanup happens while the hash spinlock is held. Technical details include the rxrpc put peer function and the rxnet->peer hash lock spinlock.
Recommendations To resolve this issue, update the Linux kernel to a version that includes the fix, which changes the spinlocks of rxnet->peer hash lock back to BH-disabling locks.
Note: The provided information does not specify the exact version that includes the fix, only that the issue is present in versions prior to 6.13.0-rc5-build2+ #1223.

Exploit

Fix

Improper Locking

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Weakness Enumeration

Related Identifiers

BDU:2025-12265
CVE-2025-21809
USN-7521-1
USN-7521-2
USN-7521-3
USN-7651-1
USN-7651-2
USN-7651-3
USN-7651-4
USN-7651-5
USN-7651-6
USN-7652-1
USN-7653-1
USN-7737-1

Affected Products

Astra Linux
Linuxmint
Linux Kernel
Ubuntu