CVE-2025-61872: Mahara Elasticsearch7 XSS Vulnerability

CVE-2025-61872 Overview

CVE-2025-61872 is a reflected cross-site scripting (XSS) vulnerability [CWE-79] in Mahara, an open-source ePortfolio and social networking platform. The flaw exists in the search site feature when the Elasticsearch7 search plugin is enabled. Mahara fails to sanitize the query parameter before rendering it in the results page, allowing attackers to inject arbitrary JavaScript through a malicious search query string. Mahara versions before 25.04.2 and before 24.04.11 are affected.

Critical Impact

Attackers can craft malicious search URLs that execute JavaScript in the victim's browser session, enabling session theft, credential harvesting, and unauthorized actions on behalf of authenticated Mahara users.

Affected Products

• Mahara versions prior to 25.04.2
• Mahara versions prior to 24.04.11
• Mahara deployments using the Elasticsearch7 search plugin

Discovery Timeline

• 2026-04-24 - CVE-2025-61872 published to NVD
• 2026-04-24 - Last updated in NVD database

Technical Details for CVE-2025-61872

Vulnerability Analysis

The vulnerability resides in Mahara's search site functionality when configured with the Elasticsearch7 search plugin. When a user submits a search query, the application passes the query parameter to the Elasticsearch backend and reflects the input back into the rendered results page. The Elasticsearch integration code does not apply HTML encoding or input sanitization to the query string before output.

An attacker can construct a URL containing a crafted query value with embedded HTML or JavaScript payloads. When a victim clicks the link or is redirected to it, the malicious payload executes in the victim's browser within the context of the Mahara application.

Because the attack requires user interaction and produces a scope change in the browser, it carries an EPSS probability of 0.031% at the 9.246 percentile, indicating low observed exploitation likelihood.

Root Cause

The root cause is missing output encoding in the Elasticsearch7 search plugin's results rendering path. User-controlled input from the query HTTP parameter flows directly into HTML output without contextual escaping. Mahara's broader search subsystem applies sanitization elsewhere, but the Elasticsearch7 plugin code path bypasses these protections.

Attack Vector

Exploitation is reflected and network-based. An attacker hosts or distributes a URL pointing to the Mahara search endpoint with a malicious query parameter. When a logged-in Mahara user follows the link, the injected script executes with the victim's privileges. Typical payloads target session cookies, CSRF tokens, or trigger authenticated requests to modify portfolios, expose private artifacts, or pivot to administrative functions if the victim holds elevated roles.

No verified proof-of-concept code is publicly available. See the Mahara Forum Discussion #9851 for vendor-provided technical details.

Detection Methods for CVE-2025-61872

Indicators of Compromise

• HTTP GET requests to Mahara search endpoints containing <script>, javascript:, onerror=, or HTML entity-encoded variants in the query parameter
• Unexpected outbound requests from user browsers to attacker-controlled domains immediately following a Mahara search action
• Web server access logs showing unusually long or URL-encoded query values targeting the site search route

Detection Strategies

• Inspect web application firewall (WAF) and reverse proxy logs for XSS signatures in query string parameters destined for Mahara search URLs
• Correlate referrer headers showing external origins followed by anomalous JavaScript execution patterns in browser telemetry
• Hunt for Mahara session cookies being transmitted to non-Mahara hosts in network egress logs

Monitoring Recommendations

• Enable verbose access logging on the Mahara web tier and forward logs to a centralized analytics platform for query parameter inspection
• Alert on HTTP 200 responses to search requests where the query parameter exceeds typical length thresholds or contains script-like tokens
• Monitor Mahara administrative account activity for unexpected configuration changes that could follow a successful session hijack

How to Mitigate CVE-2025-61872

Immediate Actions Required

• Upgrade Mahara to version 25.04.2 or 24.04.11, which contain the official fix for the Elasticsearch7 plugin sanitization gap
• Audit Mahara configuration to determine whether the Elasticsearch7 search plugin is enabled and identify exposed instances
• Review recent web server logs for suspicious query parameter values that may indicate prior exploitation attempts

Patch Information

The Mahara project addressed the vulnerability in releases 25.04.2 and 24.04.11. The patched releases add proper output encoding to the Elasticsearch7 search results rendering path. Refer to the Mahara Official Website for download links and release notes.

Workarounds

• Disable the Elasticsearch7 search plugin and revert to Mahara's internal search backend until the patch can be applied
• Deploy a WAF rule blocking requests to Mahara search endpoints where the query parameter contains HTML tags or script keywords
• Enforce a strict Content Security Policy (CSP) header to limit inline script execution and restrict script sources for the Mahara origin

# Example nginx WAF-style rule to block script-like patterns in the search query
location ~ ^/search/ {
    if ($arg_query ~* "(<script|javascript:|onerror=|onload=)") {
        return 403;
    }
    proxy_pass http://mahara_backend;
}