CVE-2025-21703
HIGHDescription
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.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 18% of all known CVEs.
References
- https://git.kernel.org/stable/c/1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5
- https://git.kernel.org/stable/c/6312555249082d6d8cc5321ff725df05482d8b83
- https://git.kernel.org/stable/c/638ba5089324796c2ee49af10427459c2de35f71
- https://git.kernel.org/stable/c/7b79ca9a1de6a428d486ff52fb3d602321c08f55
- https://git.kernel.org/stable/c/7f31d74fcc556a9166b1bb20515542de7bb939d1
- https://git.kernel.org/stable/c/839ecc583fa00fab785fde1c85a326743657fd32
- https://git.kernel.org/stable/c/98a2c685293aae122f688cde11d9334dddc5d207
- https://git.kernel.org/stable/c/e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c
- https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-03.