CVE-2025-40083

net/sched: sch_qfq: Fix null-deref in agg_dequeue

State: Published
Severity: Not scored
Published: Oct 29, 2025
Updated: Jun 16, 2026
Reserved: Apr 16, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

net/sched: sch_qfq: Fix null-deref in agg_dequeue

To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c) when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return value before using it, similar to the existing approach in sch_hfsc.c.

To avoid code duplication, the following changes are made:

1. Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static inline function.

2. Moved qdisc_peek_len from net/sched/sch_hfsc.c to include/net/pkt_sched.h so that sch_qfq can reuse it.

3. Applied qdisc_peek_len in agg_dequeue to avoid crashing.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	462dbc9101acd38e92eda93c0726857517a24bbd to before 71d84658a61322e5630c85c5388fc25e4a2d08b2Affected 462dbc9101acd38e92eda93c0726857517a24bbd to before 99fc137f178797204d36ac860dd8b31e35baa2dfAffected 462dbc9101acd38e92eda93c0726857517a24bbd to before 1bed56f089f09b465420bf23bb32985c305cfc28Affected 462dbc9101acd38e92eda93c0726857517a24bbd to before 3c2a8994807623c7655ece205667ae2cf74940aaAffected 462dbc9101acd38e92eda93c0726857517a24bbd to before 6ffa9d66187188e3068b5a3895e6ae1ee34f9199Affected 462dbc9101acd38e92eda93c0726857517a24bbd to before 6ff8e74c8f8a68ec07ef837b95425dfe900d060fAffected 462dbc9101acd38e92eda93c0726857517a24bbd to before dd831ac8221e691e9e918585b1003c7071df0379Affected
LinuxLinux	3.8Affected before 3.8Not affected 5.4.302 through 5.4.Not affected 5.10.247 through 5.10.Not affected 5.15.197 through 5.15.Not affected 6.1.159 through 6.1.Not affected 6.6.116 through 6.6.Not affected 6.12.57 through 6.12.Not affected 6.16 and laterNot affected

Product

Versions

LinuxLinux

462dbc9101acd38e92eda93c0726857517a24bbd to before 71d84658a61322e5630c85c5388fc25e4a2d08b2Affected
462dbc9101acd38e92eda93c0726857517a24bbd to before 99fc137f178797204d36ac860dd8b31e35baa2dfAffected
462dbc9101acd38e92eda93c0726857517a24bbd to before 1bed56f089f09b465420bf23bb32985c305cfc28Affected
462dbc9101acd38e92eda93c0726857517a24bbd to before 3c2a8994807623c7655ece205667ae2cf74940aaAffected
462dbc9101acd38e92eda93c0726857517a24bbd to before 6ffa9d66187188e3068b5a3895e6ae1ee34f9199Affected
462dbc9101acd38e92eda93c0726857517a24bbd to before 6ff8e74c8f8a68ec07ef837b95425dfe900d060fAffected
462dbc9101acd38e92eda93c0726857517a24bbd to before dd831ac8221e691e9e918585b1003c7071df0379Affected

LinuxLinux

3.8Affected
before 3.8Not affected
5.4.302 through 5.4.*Not affected
5.10.247 through 5.10.*Not affected
5.15.197 through 5.15.*Not affected
6.1.159 through 6.1.*Not affected
6.6.116 through 6.6.*Not affected
6.12.57 through 6.12.*Not affected
6.16 and laterNot affected

References

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