CVE-2025-38637: net_sched: skbprio: Remove overly strict queue assertions

Description

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

net_sched: skbprio: Remove overly strict queue assertions

In the current implementation, skbprio enqueue/dequeue contains an assertion
that fails under certain conditions when SKBPRIO is used as a child qdisc under
TBF with specific parameters. The failure occurs because TBF sometimes peeks at
packets in the child qdisc without actually dequeuing them when tokens are
unavailable.

This peek operation creates a discrepancy between the parent and child qdisc
queue length counters. When TBF later receives a high-priority packet,
SKBPRIO's queue length may show a different value than what's reflected in its
internal priority queue tracking, triggering the assertion.

The fix removes this overly strict assertions in SKBPRIO, they are not
necessary at all.

Classification

CVE ID: CVE-2025-38637

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 8.12% (scored less or equal to compared to others)

EPSS Date: 2025-04-18 (when was this score calculated)

References

Timeline

2025-04-18 08:40:19 UTC
CVE

net_sched: skbprio: Remove overly strict queue assertions