CVE-2025-38083 Information

Jun 21, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

net_sched: prio: fix a race in prio_tune()

Gerrard Tai reported a race condition in PRIO whenever SFQ perturb timer fires at the wrong time.

The race is as follows:

CPU 0 CPU 1 [1]: lock root [2]: qdisc_tree_flush_backlog() [3]: unlock root | | [5]: lock root | [6]: rehash | [7]: qdisc_tree_reduce_backlog() | [4]: qdisc_put()

This can be abused to underflow a parent’s qlen.

Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog() should fix the race because all packets will be purged from the qdisc before releasing the lock.

Reference

https://git.kernel.org/stable/c/46c15c9d0f65c9ba857d63f53264f4b17e8a715f https://git.kernel.org/stable/c/93f9eeb678d4c9c1abf720b3615fa8299a490845 https://git.kernel.org/stable/c/d35acc1be3480505b5931f17e4ea9b7617fea4d3 https://git.kernel.org/stable/c/e3f6745006dc9423d2b065b90f191cfa11b1b584

CNNVD-202506-2665 (Published: 2025-06-20)

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