dbcve.org
OpenslidesApplication

CVE-2026-25519

CRITICAL · 9.8 CVSS v3.1 Published 2026-02-04
Fix available
A fix is available. Upgrade to 4.2.29 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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
OpenSlides is a free, web based presentation and assembly system for managing and projecting agenda, motions and elections of an assembly. Prior to version 4.2.29, OpenSlides supports local logins with username and password or an optionally configurable single sign on with SAML via an external IDP. For users synced to OpenSlides via an external IDP, there is an incorrect access control regarding the local login of these users. Users can successfully login using the local login form and the OpenSlides username of a SAML user and a trivial password. This password is valid for all SAML users. This issue has been patched in version 4.2.29.

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

OpenSlides versions before 4.2.29 have an access control flaw in the local login mechanism. When users are synchronized from an external SAML Identity Provider (IdP), the system incorrectly allows authentication via the local login form using the SAML user's username with any arbitrary password. This trivial password works universally for all SAML-synced user accounts, enabling unauthenticated attackers to access any SAML-provisioned user's account.

MitigationUpgrade to OpenSlides version 4.2.29 or later, which contains the patch for this access control bypass. If immediate upgrade is not possible, consider disabling local login for SAML-synced users at the application or web server level as a compensating control.

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
OpenslidesApplication
Affected:>= 4.2.5, < 4.2.29

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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. Determine installed OpenSlides version
    Access the OpenSlides admin interface and navigate to System > About, or check the version file in the installation directory (version.py or similar). Alternatively, if using Docker, run 'docker ps' and inspect the image tag or check the container environment variables.
    Affected if The installed version is 4.2.5 or higher but lower than 4.2.29.
  2. Verify SAML authentication is configured
    Navigate to OpenSlides admin settings under Authentication/Auth and look for SAML/SSO configuration. Check if an external SAML Identity Provider is connected and users are being synchronized from it.
    Affected if SAML IdP integration is active and user synchronization from the external IdP is enabled.
  3. Confirm local login form is enabled
    Check the authentication settings in the OpenSlides admin panel. Look for a configuration option that allows users to log in locally using username and password (as opposed to redirecting to SAML IdP).
    Affected if Local username/password authentication is permitted for users in the system.
  4. Identify SAML-synced user accounts
    In the OpenSlides user management panel, review user accounts. Look for accounts that were created or updated via SAML synchronization (typically indicated by an 'SAML' source attribute, external ID, or sync timestamp).
    Affected if There exist user accounts that were provisioned through SAML synchronization from the external IdP.

You are affected if OpenSlides version is between 4.2.5 and 4.2.28, SAML authentication is configured with user synchronization enabled, local login is permitted, and SAML-provisioned user accounts exist in the system.

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 4.2.29 or later
Fixed in 4.2.29
Vendor patch github.com →
Interim mitigation

Upgrade to OpenSlides version 4.2.29 or later, which contains the patch for this access control bypass. If immediate upgrade is not possible, consider disabling local login for SAML-synced users at the application or web server level as a compensating control.

Recommended fix High confidence

4.2.29

  1. Verify current OpenSlides version (check admin interface or deployment configuration)
  2. Review OpenSlides upgrade documentation for your deployment method
  3. Create a backup of the OpenSlides instance including database and configuration
  4. Upgrade OpenSlides to version 4.2.29 or later
  5. After upgrade, verify that SAML users can no longer authenticate via local login with trivial passwords
  6. Confirm normal SAML-based authentication still functions correctly for external IDP users

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

Fix this in Openslides Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.

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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-2026-25519 in production — separate from our analysis above.

No notes yet

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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