CVE-2025-59308: Mahara Auth Bypass Vulnerability

CVE-2025-59308 Overview

CVE-2025-59308 is an access control vulnerability in Mahara, an open-source ePortfolio and social networking platform. The flaw affects Mahara versions before 24.04.10 and 25 before 25.04.1. On multi-tenanted sites, an institution administrator or institution support administrator can masquerade as an institution member in an institution where they hold no administrative role. Exploitation requires the attacker to also hold the Site staff role. The issue is tracked as an improper access control weakness [CWE-284].

Critical Impact

Authenticated administrators with the Site staff role can impersonate users across institution boundaries, undermining tenant isolation on multi-tenanted Mahara deployments.

Affected Products

• Mahara versions prior to 24.04.10
• Mahara 25 versions prior to 25.04.1
• Multi-tenanted Mahara site deployments

Discovery Timeline

• 2026-04-24 - CVE CVE-2025-59308 published to NVD
• 2026-04-24 - Last updated in NVD database

Technical Details for CVE-2025-59308

Vulnerability Analysis

The vulnerability resides in Mahara's masquerade functionality, which lets administrators temporarily act as another user. On multi-tenanted Mahara sites, the platform must enforce that an institution administrator can only masquerade as members of institutions they manage. This authorization check is incomplete when the administrator also holds the Site staff role.

The combined role grants an authorization path that bypasses the institution scope check. An institution administrator or institution support administrator can therefore impersonate members of institutions outside their administrative scope. The attack surface is limited to authenticated users already holding elevated roles, which constrains exploitability but does not eliminate the cross-tenant impact.

Mahara classifies this as a horizontal and vertical privilege escalation across tenancy boundaries. Once impersonating a target user, the attacker can read, modify, or submit content as that user within the affected institution.

Root Cause

The root cause is an improper access control check [CWE-284] in the masquerade workflow. The code evaluates whether the requesting account holds an administrative role but fails to confirm that the targeted user belongs to an institution the requester actually administers when the Site staff role is present.

Attack Vector

Exploitation is performed over the network through the standard Mahara web interface. The attacker authenticates with an account that holds both an institution administrator or institution support administrator role and the Site staff role. The attacker then invokes the masquerade feature against a user in an institution outside their administrative scope.

No malicious payload, memory corruption primitive, or custom tooling is required. The exploitation path follows legitimate application flows where authorization is incorrectly granted. Verified proof-of-concept code is not publicly available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2025-59308

Indicators of Compromise

• Masquerade events in Mahara application logs where the acting administrator does not belong to the target user's institution.
• Authentication or session activity for institution members originating from accounts associated with Site staff role holders.
• Unexpected content edits, page submissions, or message activity attributed to institution members shortly after a masquerade event.

Detection Strategies

• Audit Mahara database tables and application logs for become user or masquerade operations and cross-reference with institution membership records.
• Alert on any masquerade event where the source administrator's institution set does not include the target user's institution.
• Review role assignments to identify accounts that simultaneously hold institution administrator or support administrator roles and the Site staff role.

Monitoring Recommendations

• Forward Mahara web server and application logs to a centralized logging or SIEM platform for retention and correlation.
• Track changes to institutional role assignments and flag privilege combinations that enable this vulnerability.
• Monitor for anomalous session patterns where a single source IP rapidly switches between user contexts.

How to Mitigate CVE-2025-59308

Immediate Actions Required

• Upgrade Mahara to version 24.04.10 or later within the 24 release line, or to 25.04.1 or later within the 25 release line.
• Inventory accounts holding both institution administrator or institution support administrator roles together with the Site staff role and revoke unnecessary combinations.
• Review masquerade activity logs since the affected versions were deployed to identify potential abuse.

Patch Information

The Mahara project addressed CVE-2025-59308 in releases 24.04.10 and 25.04.1. Administrators should consult the Mahara Homepage and the Mahara Forum Discussion #9851 for release notes and upgrade guidance.

Workarounds

• Restrict the Site staff role to accounts that do not also hold institution administrator or institution support administrator roles until patching is complete.
• Temporarily disable the masquerade feature for non-site administrators on multi-tenanted deployments where role separation cannot be enforced.
• Increase auditing on the masquerade workflow and review logs daily until the upgrade is applied.

# Identify Mahara version on a Linux deployment
grep -R "\$config->version" /path/to/mahara/htdocs/lib/version.php

# Example role audit query (run against the Mahara database)
# Lists users holding the Site staff role for manual cross-check against institution admin roles
SELECT u.username, u.email
FROM usr u
WHERE u.staff = 1;