# CVE-2026-74300: Bluetooth: hci: validate codec capability element length

> A malformed Bluetooth controller response can cause an out-of-bounds read in the Linux kernel, potentially leading to memory corruption or system crashes.

- **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:** BELL-CVE-2026-74300, DEBIAN-CVE-2026-74300, GHSA-8wcp-4xmv-gqvg, UBUNTU-CVE-2026-74300

## What is CVE-2026-74300?

CVE-2026-74300 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:

Bluetooth: hci: validate codec capability element length

Read Local Codec Capabilities returns a sequence of capability elements.
Each element starts with a one-byte length followed by that many payload
bytes.

hci_read_codec_capabilities() checks that the skb contains the length
byte, but then validates only caps->len against the remaining skb
length.  A malformed controller response with one remaining byte and
caps->len set to one passes that check even though the element needs two
bytes.  The parser then records a two-byte capability and copies one
byte beyond the advertised response payload into the codec list.

Validate the full element size, including the length byte, before adding
it to the accumulated capability length.  This preserves all well-formed
capability elements and drops only truncated controller responses.

## Which versions are affected by CVE-2026-74300?


## How do I fix CVE-2026-74300?

Apply the vendor's patch.

## Is CVE-2026-74300 being exploited?

There is no known exploitation of CVE-2026-74300 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74300 and fix it if it is affected.

What it is: CVE-2026-74300 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-2026-74300 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-2026-74300/ (Markdown: https://insights.sbomify.com/CVE-2026-74300/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74300
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74300
- OSV: https://osv.dev/vulnerability/CVE-2026-74300

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74300/
Summaries are generated and may contain mistakes; the official description above is the record.