CVE intelligence and bounded remediation

CVE-2026-25519 — OpenSlides is a free, web based presentation and assembly system for managing and projecting agenda, motions and elections of an assembly

Critical CVSS 9.8

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.

Severity
Critical
CVSS
9.8 (3.1)
Published
2026-02-04
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-284

Affected products

  • openslides / openslides

Matched remediation archetype

Authorization bypass, IDOR, and cross-tenant access

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
  • Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
  • Use synthetic fixtures to compare intended access matrices without accessing another user's real data.

Remediate safely

  • Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
  • Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
  • Add deny-by-default policy tests for horizontal and vertical access across every affected transport.

Authoritative sources

Complete CVE record and remediation plan

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