# CVE-2026-74649: staging: rtl8723bs: fix missing shared-key auth challenge length check

> A malicious access point can trigger a buffer overflow or leak memory in the rtl8723bs Wi-Fi driver during shared-key authentication, potentially leading to code execution or data disclosure.

- **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:** 22 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74649, DEBIAN-CVE-2026-74649, GHSA-3j7p-mfvr-mgx3, UBUNTU-CVE-2026-74649

## What is CVE-2026-74649?

CVE-2026-74649 is a high-severity memory corruption vulnerability in Linux, published on 22 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:

staging: rtl8723bs: fix missing shared-key auth challenge length check

The WEP shared-key authentication handler uses the challenge-text
element's attacker-controlled length without checking it against the
fixed 128-byte chg_txt buffer.

In OnAuthClient() the length from rtw_get_ie() - up to 255 - is used
to perform memcpy() into the 128-byte pmlmeinfo->chg_txt, so a
malicious AP sending a malformed WLAN_EID_CHALLENGE element can
overflow/underfill chg_txt by up to 127 bytes. It is reachable over the
air, before association, during shared-key authentication. In the case
of an overflow, the driver can write out of bounds. In the case of an
underfill, the driver can echo stale buffer memory.

The challenge text is defined to be exactly 128 octets, which is
already provided as the WLAN_AUTH_CHALLENGE_LEN define; require the
element to be exactly that length before use.

## Which versions are affected by CVE-2026-74649?


## How do I fix CVE-2026-74649?

Apply the vendor's patch.

## Is CVE-2026-74649 being exploited?

There is no known exploitation of CVE-2026-74649 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74649 and fix it if it is affected.

What it is: CVE-2026-74649 is a high-severity memory corruption vulnerability in Linux, published on 22 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-2026-74649 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-2026-74649/ (Markdown: https://insights.sbomify.com/CVE-2026-74649/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74649
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74649
- OSV: https://osv.dev/vulnerability/CVE-2026-74649

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74649/
Summaries are generated and may contain mistakes; the official description above is the record.