# CVE-2026-90017: staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()

> A missing length check in the rtl8723bs driver allows an attacker to trigger an out-of-bounds read, potentially disclosing kernel memory.

- **Severity:** High 7.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101631, BELL-CVE-2026-90017, DEBIAN-CVE-2026-90017, GHSA-9fp4-x69f-gf9f, UBUNTU-CVE-2026-90017

## What is CVE-2026-90017?

CVE-2026-90017 is a high-severity vulnerability in Linux, published on 16 Sep 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:

staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()

rtw_action_frame_parse() takes a frame_len parameter but never
actually checks it before indexing into the frame body:

	const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr);
	...
	c = frame_body[0];
	...
	a = frame_body[1];

frame_body already points 24 bytes (sizeof(struct
ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and
frame_body[1] requires frame_len >= 26. A management action frame
shorter than that (e.g. exactly 24 bytes, the minimum a malicious
peer can send) causes a 1-2 byte out-of-bounds read.

This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and
cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass
attacker/user-influenced frame buffers and lengths straight through.

Add the missing length check before frame_body is dereferenced.

## Which versions are affected by CVE-2026-90017?


## How do I fix CVE-2026-90017?

Apply the vendor's patch.

## Is CVE-2026-90017 being exploited?

There is no known exploitation of CVE-2026-90017 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90017 and fix it if it is affected.

What it is: CVE-2026-90017 is a high-severity vulnerability in Linux, published on 16 Sep 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-2026-90017 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-2026-90017/ (Markdown: https://insights.sbomify.com/CVE-2026-90017/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90017
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90017
- OSV: https://osv.dev/vulnerability/CVE-2026-90017

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90017/
Summaries are generated and may contain mistakes; the official description above is the record.