debian · CVE-2025-21703

Quick triage

Priority: not yet assigned Published: Updated: Mon, 20 Jul 2026 12:32:35 GMT

View at Official debian advisory, NVD, CVE.org · CVE detail

Freshness: upstream tracker timestamp is available; use API updated time as primary recency signal.

Tracker summary

CVE-2025-21703 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6.

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.

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