Detections
Analytics
CVE-2025-21703
high
Description
In the Linux kernel, the following vulnerability has been resolved: netem: Update sch->q.qlen before qdisc_tree_reduce_backlog() qdisc_tree_reduce_backlog() notifies parent qdisc only if child qdisc becomes empty, therefore we need to reduce the backlog of the child qdisc before calling it. Otherwise it would miss the opportunity to call cops->qlen_notify(), in the case of DRR, it resulted in UAF since DRR uses ->qlen_notify() to maintain its active list.
References
https://git.kernel.org/stable/c/839ecc583fa00fab785fde1c85a326743657fd32
https://git.kernel.org/stable/c/7b79ca9a1de6a428d486ff52fb3d602321c08f55
https://git.kernel.org/stable/c/638ba5089324796c2ee49af10427459c2de35f71
https://git.kernel.org/stable/c/6312555249082d6d8cc5321ff725df05482d8b83
https://git.kernel.org/stable/c/1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5