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

> A local attacker can trigger a kernel assertion failure in the skbprio qdisc, causing a system crash or denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Apr 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-38637, DEBIAN-CVE-2025-38637, GHSA-9ghj-mrhr-8wxx, ROOT-OS-UBUNTU-2404-CVE-2025-38637, UBUNTU-CVE-2025-38637

## What is CVE-2025-38637?

CVE-2025-38637 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 18 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2025-38637?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38637?

Apply the vendor's patch.

## Is CVE-2025-38637 being exploited?

There is no known exploitation of CVE-2025-38637 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38637 and fix it if it is affected.

What it is: CVE-2025-38637 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 18 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-38637 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-38637/ (Markdown: https://insights.sbomify.com/CVE-2025-38637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38637
- OSV: https://osv.dev/vulnerability/CVE-2025-38637

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38637/
Summaries are generated and may contain mistakes; the official description above is the record.