# CVE-2026-74554: wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup()

> An out-of-bounds write in the ath12k WiFi driver corrupts memory, potentially causing denial of service or code execution in the Linux kernel.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-74554, GHSA-m2x9-5x38-cjm5, UBUNTU-CVE-2026-74554

## What is CVE-2026-74554?

CVE-2026-74554 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. 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:

wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup()

ath12k_mac_dp_peer_cleanup() clears the ML peer ID slot on the
free_ml_peer_id_map bitmap by indexing it with dp_peer->peer_id. That is
wrong: dp_peer->peer_id for an MLO peer always carries the
ATH12K_PEER_ML_ID_VALID bit (BIT(13)), so clear_bit() is invoked with
index >= 0x2000, which is far outside the bitmap of ATH12K_MAX_MLO_PEERS
(256) bits and corrupts memory adjacent to ah->free_ml_peer_id_map. The
intended bitmap entry also never gets cleared, so subsequent
ath12k_peer_ml_alloc() calls eventually run out of IDs.

The ID without the VALID bit is what ath12k_peer_ml_alloc() returned and
is stored in ahsta->ml_peer_id. Use that instead.

While there, also reset ahsta->ml_peer_id to ATH12K_MLO_PEER_ID_INVALID so
the bitmap and ahsta->ml_peer_id stay in sync.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3

## Which versions are affected by CVE-2026-74554?


## How do I fix CVE-2026-74554?

Apply the vendor's patch.

## Is CVE-2026-74554 being exploited?

There is no known exploitation of CVE-2026-74554 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74554 and fix it if it is affected.

What it is: CVE-2026-74554 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. 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-2026-74554 in the wild and no public exploit code.

Affected product: 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-2026-74554/ (Markdown: https://insights.sbomify.com/CVE-2026-74554/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74554
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74554
- OSV: https://osv.dev/vulnerability/CVE-2026-74554

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74554/
Summaries are generated and may contain mistakes; the official description above is the record.