CVE-2025-68325None▾ TwilightPoC availableIn 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 hierarch…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 2.8 · likelihood 0 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Public exploit / PoC code seen in 1 source. Availability, not in-the-wild use.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.2%
1 GitHub repo (last check)
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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.