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OpenprojectApplication

CVE-2026-23646

MEDIUM · 6.5 CVSS v3.1 Published 2026-01-19
Fix available
A fix is available. Upgrade to 16.6.5 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
OpenProject is an open-source, web-based project management software. Users of OpenProject versions prior to 16.6.5 and 17.0.1 have the ability to view and end their active sessions via Account Settings → Sessions. When deleting a session, it was not properly checked if the session belongs to the user. As the ID that is used to identify these session objects use incremental integers, users could iterate requests using `DELETE /my/sessions/:id` and thus unauthenticate other users. Users did not have access to any sensitive information (like browser identifier, IP addresses, etc) of other users that are stored in the session. The problem was patched in OpenProject versions 16.6.5 and 17.0.1. No known workarounds are available as this does not require any permissions or other that can temporarily be disabled.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

OpenProject before 16.6.5 and 17.0.1 contains an IDOR (Insecure Direct Object Reference) vulnerability in the session management endpoint. The DELETE /my/sessions/:id endpoint did not verify that the session being deleted belongs to the authenticated user, allowing attackers to iterate through incremental session IDs and forcibly unauthenticate other users.

MitigationUpgrade to OpenProject version 16.6.5 or 17.0.1 or later. No workarounds exist as this vulnerability does not require special permissions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OpenprojectApplication
Affected:< 16.6.5= 17.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed OpenProject version
    Log in as an administrator and navigate to Administration > Information, or check the OpenProject API endpoint /api/v3/version, or look for a VERSION file in the application root
    Affected if The version displayed is less than 16.6.5 or equals 17.0.0 exactly
  2. Verify session management endpoint exists
    Attempt to access the DELETE /my/sessions/:id endpoint by making an HTTP DELETE request to /my/sessions/1 (authenticated as any user)
    Affected if The endpoint responds (even with an error) indicating the session management feature is active
  3. Confirm user sessions are stored in the database
    Check if OpenProject is configured to use database-backed sessions by reviewing config/configuration.yml or the session_store configuration in config/initializers/session_store.rb
    Affected if Database-backed sessions are enabled (the default configuration) - this is required for the IDOR to be exploitable

A user is affected if their OpenProject installation version is less than 16.6.5 or exactly 17.0.0 and the session management feature is active with database-backed sessions enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 16.6.5 or later
Fixed in 16.6.5
Interim mitigation

Upgrade to OpenProject version 16.6.5 or 17.0.1 or later. No workarounds exist as this vulnerability does not require special permissions.

Recommended fix High confidence

OpenProject 16.6.5+ (stable/16) or 17.0.1+ (stable/17)

  1. Identify your current OpenProject version by checking the admin panel or running `openproject --version`
  2. If running version 16.x (prior to 16.6.5), upgrade to version 16.6.5 or later in the 16.x stable branch
  3. If running version 17.0.0, upgrade to version 17.0.1 or later in the 17.x stable branch
  4. Follow the official OpenProject upgrade documentation for your installation method (e.g., packaged installation, Docker, or source)
  5. After upgrade, verify the fix by attempting to access a session ID that does not belong to your user - the API should return a 403 Forbidden error
  6. Test that legitimate session deletion via Account Settings → Sessions still functions correctly
Caveat Review release notes for 16.6.5 and 17.0.1 for any breaking changes before upgrading; major version upgrades (e.g., 16.x to 17.x) may have breaking changes requiring migration testing

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Openproject Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23646 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data