# CVE-2025-23155: net: stmmac: Fix accessing freed irq affinity_hint

> An unprivileged user can trigger a use-after-free in the stmmac driver via procfs, causing kernel crashes or leaking kernel memory.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:** 1 May 2025
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-62601, AZL-69668, BELL-CVE-2025-23155, DEBIAN-CVE-2025-23155, GHSA-w4x2-878r-xjgp, ROOT-OS-DEBIAN-12-CVE-2025-23155, ROOT-OS-UBUNTU-2204-CVE-2025-23155, ROOT-OS-UBUNTU-2404-CVE-2025-23155, UBUNTU-CVE-2025-23155

## What is CVE-2025-23155?

CVE-2025-23155 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 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: 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.

## Which versions are affected by CVE-2025-23155?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-23155?

Apply the vendor's patch.

## Is CVE-2025-23155 being exploited?

There is no known exploitation of CVE-2025-23155 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-23155 and fix it if it is affected.

What it is: CVE-2025-23155 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 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-2025-23155 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-23155/ (Markdown: https://insights.sbomify.com/CVE-2025-23155/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-23155
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-23155
- OSV: https://osv.dev/vulnerability/CVE-2025-23155

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-23155/
Summaries are generated and may contain mistakes; the official description above is the record.