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CVE-2025-38637

MEDIUMCVSS 5.5/10EPSS 0.24%

Last modified

CVE-2025-38637 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.24% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.24%

14.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 4.19, < 5.4.292
LinuxLinux Kernel>= 5.5, < 5.10.236
LinuxLinux Kernel>= 5.11, < 5.15.180
LinuxLinux Kernel>= 5.16, < 6.1.134
LinuxLinux Kernel>= 6.2, < 6.6.87
LinuxLinux Kernel>= 6.7, < 6.12.23
LinuxLinux Kernel>= 6.13, < 6.13.11
LinuxLinux Kernel>= 6.14, < 6.14.2
DebianDebian Linux11.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2025-38637?
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.
How severe is CVE-2025-38637?
CVE-2025-38637 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.
How do I fix CVE-2025-38637?
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.

Are you affected by CVE-2025-38637?

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Source: NVD / NIST