CVE-2025-68325: In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop In cake_drop(), q...

Description

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.

Metrics

EPSS Probability

0.18%

7.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= de04ddd2980b48caa8d7e24a7db2742917a8b280, < a3f4e3de41a3f115db35276c6b186ccbc913934a; >= 0dacfc5372e314d1219f03e64dde3ab495a5a25e, < 38abf6e931b169ea88d7529b49096f53a5dcf8fe; >= 710866fc0a64eafcb8bacd91bcb1329eb7e5035f, < fcb91be52eb6e92e00b533ebd7c77fecada537e1; >= aa12ee1c1bd260943fd6ab556d8635811c332eeb, < d01f0e072dadb02fe10f436b940dd957aff0d7d4; >= ff57186b2cc39766672c4c0332323933e5faaa88, < 0b6216f9b3d1c33c76f74511026e5de5385ee520; >= 15de71d06a400f7fdc15bf377a2552b0ec437cf5, < 529c284cc2815c8350860e9a31722050fe7117cb; >= 15de71d06a400f7fdc15bf377a2552b0ec437cf5, < 3ed6c458530a547ed0c9ea0b02b19bab620be88b; >= 15de71d06a400f7fdc15bf377a2552b0ec437cf5, < 9fefc78f7f02d71810776fdeb119a05a946a27cc; 7689ab22de36f8db19095f6bdf11f28cfde92f5c; 62d591dde4defb1333d202410609c4ddeae060b3; >= 5.10.241, < 5.10.248; >= 5.15.190, < 5.15.198; >= 6.1.149, < 6.1.160; >= 6.6.103, < 6.6.120; >= 6.12.44, < 6.12.63; >= 5.4.297, < 5.5; >= 6.16.4, < 6.17
Linux	Linux	6.17

References

Timeline

Published: Dec 18, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-68325?

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.

How severe is CVE-2025-68325?

Severity scoring for CVE-2025-68325 is pending analysis. The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.

How do I fix CVE-2025-68325?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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