VULNERABILITY INTELLIGENCE

CVE-2025-21703

CVSS score7.8 HIGH
EPSS probability0.30%
CISA KEVNot currently listed
Published2025-02-18
Last modified2026-10-15
CVSS vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

Weakness classification

  • 134c704f-9b21-4f2e-91b3-4a467353bcc0: CWE-416

Primary references