CVE-2026-33251 in Discourse
Summary
by MITRE • 03/21/2026
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an authorization bypass vulnerability in hidden Solved topics may allow unauthorized users to accept or unaccept solutions. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, ensure only trusted users are part of the Site Setting for accept_all_solutions_allowed_groups.
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Analysis
by VulDB Data Team • 03/27/2026
The vulnerability identified as CVE-2026-33251 affects Discourse, an open-source discussion platform that serves as a collaborative forum for communities and organizations. This authorization bypass flaw specifically targets the handling of hidden Solved topics within the platform's permission model. The issue manifests when users attempt to accept or unaccept solutions to topics that have been marked as solved, but are hidden from public view. The vulnerability exists in versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, representing a significant security gap that could allow unauthorized access to administrative functions within the discussion platform.
The technical implementation of this vulnerability stems from insufficient access controls within the Discourse platform's topic management system. When topics are marked as solved and hidden, the application fails to properly validate user permissions before allowing actions to accept or unaccept solutions. This flaw represents a classic authorization bypass vulnerability, where the system does not adequately verify whether the requesting user possesses the necessary privileges to perform the requested action. The underlying issue likely resides in the application's permission checking logic, where the system fails to properly distinguish between different user roles when processing solution acceptance operations on hidden topics.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially compromise the integrity of discussion threads and community moderation efforts. An attacker with access to the platform could manipulate the resolution status of topics, potentially marking incorrect solutions as accepted or removing valid solutions from consideration. This capability undermines the trust model that Discourse relies upon for community-driven problem solving and could lead to misinformation propagation within discussion forums. The vulnerability particularly affects collaborative environments where community members contribute to problem-solving processes and where the acceptance of solutions serves as a quality control mechanism.
Organizations deploying Discourse platforms should prioritize updating to the patched versions 2026.3.0-latest.1, 2026.2.1, or 2026.1.2 to remediate this security gap. The workaround suggested in the advisory, restricting the Site Setting for accept_all_solutions_allowed_groups to only trusted users, provides a temporary mitigation strategy but does not address the root cause of the authorization bypass. This vulnerability aligns with CWE-285, which addresses improper authorization within software systems, and could potentially map to ATT&CK technique T1078.004, which covers valid accounts with administrative privileges, though the specific bypass mechanism suggests a more fundamental access control flaw. The patch implementation in the newer versions likely addresses the missing permission checks in the topic solution acceptance workflow, ensuring that only users with appropriate privileges can modify solution status for hidden topics.