CVE-2021-26723: Jenzabar XSS Vulnerability

CVE-2021-26723 Overview

CVE-2021-26723 is a reflected Cross-Site Scripting (XSS) vulnerability affecting Jenzabar 9.2.x through 9.2.2. The flaw exists in the /ics endpoint, where the query parameter passed to the tool=search function is rendered without proper sanitization. Attackers can craft a malicious URL that, when visited by an authenticated user, executes arbitrary JavaScript in the victim's browser session. Jenzabar is widely deployed across higher education institutions for student information and campus management, making affected portals an attractive target for credential theft and session hijacking.

Critical Impact
Successful exploitation enables attackers to execute arbitrary JavaScript in the victim's browser context, leading to session theft, credential harvesting, and unauthorized actions on the Jenzabar portal.

Affected Products

Jenzabar 9.2.0
Jenzabar 9.2.1
Jenzabar 9.2.2

Discovery Timeline

2021-02-06 - CVE-2021-26723 published to NVD
2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-26723

Vulnerability Analysis

The vulnerability is classified as Cross-Site Scripting [CWE-79]. It resides in the Jenzabar Internet Campus Solution (ICS) search functionality exposed at /ics?tool=search&query=. The query parameter accepts user-supplied input and reflects it back in the rendered HTML response without encoding or sanitizing special characters. Attackers can inject HTML and JavaScript payloads directly through the URL.

Because the payload executes in the context of the Jenzabar application origin, it inherits the privileges of the authenticated user. This includes access to session cookies, CSRF tokens, and any data the user can view within the portal. The flaw is exploitable over the network with low complexity and requires only that a victim click a crafted link.

Root Cause

The root cause is improper neutralization of user-controlled input in the search component. The application fails to apply output encoding when rendering the query value within the response page. Standard mitigations such as HTML entity encoding or content security policy enforcement are absent in the affected versions.

Attack Vector

Exploitation requires user interaction. An attacker crafts a URL containing a JavaScript payload in the query parameter and delivers it through phishing emails, forum posts, or instant messages. When a logged-in Jenzabar user opens the link, the injected script runs in their browser. Public technical analysis of this vulnerability is available in the Medium write-up on CVE-2021-26723 and the Packet Storm advisory, with proof-of-concept code published as a GitHub Gist.

Detection Methods for CVE-2021-26723

Indicators of Compromise

Web server access logs containing requests to /ics?tool=search&query= with <script>, onerror=, javascript:, or URL-encoded equivalents in the query string.
Unusual outbound requests from user browsers to attacker-controlled domains following Jenzabar portal access.
Session cookie or token exfiltration patterns in proxy and DNS logs correlated with Jenzabar usage.

Detection Strategies

Deploy web application firewall (WAF) rules that inspect the query parameter on /ics for HTML tags, event handlers, and script keywords.
Implement server-side logging of full request URLs and review entries containing suspicious encoded characters such as %3Cscript%3E.
Correlate browser-based telemetry with portal authentication events to flag scripts loaded from non-Jenzabar origins.

Monitoring Recommendations

Monitor the EPSS score of 64.083% (98th percentile), which indicates a high likelihood of opportunistic exploitation attempts.
Alert on repeated GET requests to the search endpoint from external referrers or unusual user agents.
Track help-desk reports of unexpected pop-ups, redirects, or session terminations from portal users.

How to Mitigate CVE-2021-26723

Immediate Actions Required

Upgrade Jenzabar to a release later than 9.2.2 that addresses the search parameter sanitization issue.
Restrict access to the /ics portal to trusted networks or behind a VPN where institutional policy allows.
Educate portal users on the risk of clicking unverified links pointing to the Jenzabar domain.

Patch Information

Jenzabar has not published a dedicated CVE advisory in the references provided. Administrators should consult the Jenzabar Blog and contact Jenzabar support directly to obtain the latest patched release and remediation guidance for affected 9.2.x deployments.

Workarounds

Deploy a WAF rule to block or sanitize requests to /ics?tool=search&query= containing <, >, ", ', or known XSS payload signatures.
Configure a strict Content-Security-Policy header on the Jenzabar application to disallow inline scripts and untrusted script sources.
Set the HttpOnly and Secure flags on session cookies to limit the impact of successful script execution.

bash

# Example WAF rule (ModSecurity) to block reflected XSS in the Jenzabar search parameter
SecRule REQUEST_URI "@rx /ics\?.*tool=search" \
    "chain,deny,status:403,id:1026723,msg:'Blocked CVE-2021-26723 XSS attempt'"
    SecRule ARGS:query "@rx (?i)(<script|onerror=|onload=|javascript:|%3Cscript)" "t:none"