CVE-2025-38107 Information

Jul 04, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

net_sched: ets: fix a race in ets_qdisc_change()

Gerrard Tai reported a race condition in ETS 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/0383b25488a545be168744336847549d4a2d3d6c https://git.kernel.org/stable/c/073f64c03516bcfaf790f8edc772e0cfb8a84ec3 https://git.kernel.org/stable/c/0b479d0aa488cb478eb2e1d8868be946ac8afb4f https://git.kernel.org/stable/c/347867cb424edae5fec1622712c8dd0a2c42918f https://git.kernel.org/stable/c/d92adacdd8c2960be856e0b82acc5b7c5395fddb https://git.kernel.org/stable/c/eb7b74e9754e1ba2088f914ad1f57a778b11894b https://git.kernel.org/stable/c/fed94bd51d62d2e0e006aa61480e94e5cd0582b0

CNNVD-202507-193 (Published: 2025-07-03)

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