Security readout for executives and security teams
Plain-English summary
OpenProject may expose group membership information to users who should not see it. A logged-in user with “View Members” permission in any project could list all groups and see their members. This is a confidentiality issue, not a data modification or service outage issue.
Executive priority
Prioritize remediation in the normal patch cycle unless group membership reveals sensitive teams or customer/project relationships. In those environments, accelerate the upgrade because the issue can expose internal structure to ordinary authenticated users.
Technical view
CVE-2026-23721 is a CWE-862 missing authorization flaw in OpenProject group membership visibility checks. Before 16.6.5 and in 17.0.0, a low-privileged authenticated user with any project-level “View Members” permission could enumerate all groups and view user membership. CVSS 3.1 score is 4.3.
Likely exposure
Exposure applies to OpenProject versions prior to 16.6.5 and version 17.0.0 when groups are used to manage users. Risk is higher where group membership reveals sensitive teams, roles, projects, or organizational structure.
Exploitation context
The issue is network-accessible and requires a logged-in user with low privileges. The provided sources do not report active exploitation, and it is not listed as KEV in the supplied data. No public workaround is named in the advisory.
Researcher notes
The advisory states the intended rule: group members should only be visible to users with “View Members” in a project where that group is also a member. The failed permission check broadened visibility to all groups. Sources name fixed versions but no workaround.
Mitigation direction
- Upgrade OpenProject to 17.0.1 or 16.6.5.
- If immediate upgrade is not possible, check OpenProject vendor guidance.
- Review whether group membership names expose sensitive business context.
- Limit “View Members” permission to users with a clear business need.
Validation and detection
- Inventory OpenProject instances and record installed versions.
- Confirm whether the deployment uses groups to manage users.
- Review roles granting “View Members” permission across projects.
- After upgrading, verify the installed version is 17.0.1 or 16.6.5 or later.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-862: Authorization and privilege behavior lookup
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Open ATT&CK lookupCVE-2026-23721 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/opf/openproject/security/advisories/GHSA-vj77-wrc2-5h5hCVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.