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.
Affected products
linux: linux kernel; debian: debian linux
References10
- git.kernel.org/stable/c/20f68e6a9e41693cb0e55e5b9ebbcb40983a4b8f Patch
- git.kernel.org/stable/c/3aaa7c01cf19d9b9bb64b88b65c3a6fd05da2eb4 Patch
- git.kernel.org/stable/c/4483d8b9127591c60c4eb789d6cab953bc4522a9 Patch
- git.kernel.org/stable/c/46c15c9d0f65c9ba857d63f53264f4b17e8a715f Patch
- git.kernel.org/stable/c/53d11560e957d53ee87a0653d258038ce12361b7 Patch
- git.kernel.org/stable/c/93f9eeb678d4c9c1abf720b3615fa8299a490845 Patch
- git.kernel.org/stable/c/d35acc1be3480505b5931f17e4ea9b7617fea4d3 Patch
- git.kernel.org/stable/c/e3f6745006dc9423d2b065b90f191cfa11b1b584 Patch
- lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory
- lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory
Metrics
- CVSS 3.1
-
4.7
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 5 · as of 7 November 2026
- CWE
- CWE-362
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