CVE-2026-42164 Overview
CVE-2026-42164 is an information disclosure vulnerability in Mahara, an open-source electronic portfolio and social networking application. The flaw resides in the Text block/section functionality. Attackers can craft a specific call that recalls backed-up content from another Text section without authorization. This exposes content that should remain isolated between users or portfolio owners. The issue affects Mahara versions before 25.04.5 and 26.04.0. The vulnerability is classified under [CWE-200: Exposure of Sensitive Information to an Unauthorized Actor].
Critical Impact
Unauthenticated network-based attackers can retrieve backed-up Text section content from other users, resulting in unauthorized disclosure of potentially sensitive portfolio data.
Affected Products
- Mahara versions prior to 25.04.5
- Mahara versions prior to 26.04.0
- Mahara Text block/section functionality
Discovery Timeline
- 2026-08-17 - CVE-2026-42164 published to the National Vulnerability Database
- 2026-08-18 - Last updated in NVD database
Technical Details for CVE-2026-42164
Vulnerability Analysis
Mahara stores backup copies of Text block/section content to support versioning and recovery. The vulnerable code path fails to enforce ownership or access checks when a request references a backed-up Text section. An attacker can craft a request that resolves to a Text section belonging to another user or view. The application returns the stored content without validating the caller's authorization to read it. This maps to [CWE-200], where sensitive information is exposed to an unauthorized actor across the network.
Root Cause
The root cause is missing or insufficient authorization enforcement in the Text block/section retrieval logic. The application trusts identifiers supplied in the request to locate backed-up content. It does not verify that the requesting user owns or has permission to view the referenced Text section. This is a broken access control defect surfaced as information disclosure.
Attack Vector
Exploitation occurs over the network against a reachable Mahara instance. The attacker crafts a call to the Text block or section handler that references a backup identifier tied to another user's content. No user interaction from the victim is required. Successful exploitation returns the backed-up Text data to the attacker. Additional technical context is available in the Mahara Forum Discussion #10057 and on the Mahara Official Website.
No verified proof-of-concept code has been published. See the referenced Mahara advisory and forum thread for further details.
Detection Methods for CVE-2026-42164
Indicators of Compromise
- Unexpected HTTP requests to Text block or Text section endpoints referencing identifiers not owned by the requesting user
- Elevated volume of read operations against backup or revision tables for Text content
- Application log entries showing the same authenticated session or IP repeatedly retrieving distinct Text section identifiers
Detection Strategies
- Review Mahara application logs for requests to Text block handlers that reference block or section IDs across multiple user accounts
- Correlate web server access logs with database query logs to identify enumeration of backup content identifiers
- Deploy Web Application Firewall (WAF) rules that flag sequential or brute-force patterns against Text block endpoints
Monitoring Recommendations
- Enable verbose access logging for Mahara portfolio endpoints and retain logs for post-incident analysis
- Alert on anonymous or low-privilege sessions issuing high volumes of Text section read requests
- Monitor outbound response sizes from Text block endpoints for anomalies that could indicate bulk content extraction
How to Mitigate CVE-2026-42164
Immediate Actions Required
- Upgrade Mahara to version 25.04.5, 26.04.0, or later without delay
- Audit access logs for the Text block and Text section endpoints going back to the earliest available retention window
- Rotate credentials and review portfolio content for any user whose Text sections may have been exposed
Patch Information
The Mahara project has released fixed versions 25.04.5 and 26.04.0 that resolve the missing authorization check in the Text block/section functionality. Administrators should download the updated release from the Mahara Official Website and follow standard upgrade procedures. Verify the deployment version after upgrade and confirm that Text block backups can no longer be recalled across ownership boundaries.
Workarounds
- Restrict network access to the Mahara instance to authenticated users on trusted networks until patching is complete
- Temporarily disable the Text block feature or limit portfolio sharing scope if immediate patching is not feasible
- Apply WAF rules that block requests to Text section handlers containing identifiers not associated with the authenticated session
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
