CVE-2025-68325: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop In cake_drop(), qdisc_tree_reduce_backlog() is used to update the qlen and backlog of the qdisc hierarchy. Its caller, cake_enqueue(), assumes that the parent qdisc will enqueue the current packet. However, this assumption breaks when cake_enqueue() returns NET_XMIT_CN: the parent qdisc stops enqueuing current packet, leaving the tree qlen/backlog accounting inconsistent. This mismatch can lead to a NULL dereference (e.g., when the parent Qdisc is qfq_qdisc). This patch computes the qlen/backlog delta in a more robust way by observing the difference before and after the series of cake_drop() calls, and then compensates the qdisc tree accounting if cake_enqueue() returns NET_XMIT_CN. To ensure correct compensation when ACK thinning is enabled, a new variable is introduced to keep qlen unchanged.

Affected products

• Linux Linux: from 5.10.241, before 5.10.248 (fixed in 5.10.248); from 5.15.190, before 5.15.198 (fixed in 5.15.198); from 6.1.149, before 6.1.160 (fixed in 6.1.160); from 6.6.103, before 6.6.120 (fixed in 6.6.120); from 6.12.44, before 6.12.63 (fixed in 6.12.63); from 5.4.297, before 5.5 (fixed in 5.5); …

Published 2025-12-18. Last modified 2026-06-17.