CVE-2026-34822: Endian Firewall Stored XSS Vulnerability

CVE-2026-34822 Overview

CVE-2026-34822 is a stored cross-site scripting (XSS) vulnerability affecting Endian Firewall version 3.3.25 and prior releases. The vulnerability exists in the certificate management functionality, specifically in the new_cert_name parameter used by the /manage/ca/certificate/ endpoint. An authenticated attacker can inject arbitrary JavaScript code that is persistently stored on the server and executed whenever other users access the affected page.

Critical Impact

Authenticated attackers can inject persistent malicious scripts that execute in the context of other administrative users' sessions, potentially leading to session hijacking, credential theft, or further administrative actions performed on behalf of compromised users.

Affected Products

• Endian Firewall version 3.3.25
• Endian Firewall versions prior to 3.3.25
• Endian Firewall Community Edition (affected versions)

Discovery Timeline

• 2026-04-02 - CVE-2026-34822 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2026-34822

Vulnerability Analysis

This stored XSS vulnerability (CWE-79) occurs due to improper neutralization of user-supplied input in the certificate management interface. When an authenticated user creates or modifies a certificate through the /manage/ca/certificate/ endpoint, the new_cert_name parameter value is stored without adequate sanitization or output encoding. The malicious payload persists in the application database and is rendered without proper escaping when the certificate listing or details page is viewed by any user with access to the certificate management functionality.

The network-accessible attack vector combined with the requirement for low privileges (authenticated access) means that any user with certificate management permissions can exploit this vulnerability. The stored nature of the XSS makes it particularly dangerous as the attack is persistent and affects all subsequent viewers of the compromised page.

Root Cause

The root cause of CVE-2026-34822 is insufficient input validation and output encoding in the Endian Firewall's certificate management module. The application fails to properly sanitize the new_cert_name parameter before storing it in the database and does not apply appropriate HTML entity encoding when rendering the certificate name in web pages. This allows HTML and JavaScript content to be interpreted by the browser rather than displayed as plain text.

Attack Vector

The attack is executed over the network by an authenticated user with access to certificate management features. The attacker crafts a malicious certificate name containing JavaScript code and submits it through the /manage/ca/certificate/ endpoint. Once stored, the payload executes in the browsers of any users who view the certificate listing or details pages.

The exploitation flow typically involves:

1. An authenticated attacker navigates to the certificate management interface
2. The attacker creates a new certificate with a malicious name containing JavaScript payload (e.g., <script>alert(document.cookie)</script>)
3. The application stores the unsanitized input
4. When administrators or other users view the certificate list, the malicious script executes in their browser context
5. The attacker can exfiltrate session tokens, perform actions as the victim, or inject additional malicious content

For detailed technical information about this vulnerability, refer to the VulnCheck Advisory for Endian.

Detection Methods for CVE-2026-34822

Indicators of Compromise

• Unusual JavaScript code or HTML tags present in certificate names within the Endian Firewall database
• Unexpected outbound connections from administrative workstations after accessing the certificate management interface
• Web application logs showing certificate names containing <script>, javascript:, onerror=, or similar XSS patterns
• Session tokens or credentials being transmitted to unknown external domains

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block XSS payloads in POST requests to /manage/ca/certificate/
• Enable Content Security Policy (CSP) headers to restrict script execution and report policy violations
• Deploy browser-based XSS auditors and monitor for blocked script executions on the firewall management interface
• Perform regular database audits to identify certificate entries containing suspicious HTML or JavaScript content

Monitoring Recommendations

• Monitor HTTP request logs for POST requests to /manage/ca/certificate/ containing encoded or plaintext script tags
• Configure alerting for any Content-Security-Policy violation reports originating from the Endian Firewall management interface
• Track administrative session activity for anomalous behavior patterns following access to certificate management pages
• Enable verbose logging on the Endian Firewall management interface and correlate with endpoint detection events

How to Mitigate CVE-2026-34822

Immediate Actions Required

• Restrict access to the certificate management interface (/manage/ca/certificate/) to only essential administrative personnel
• Audit existing certificate entries for any suspicious or malicious content and remove compromised records
• Implement network-level access controls to limit who can reach the Endian Firewall administrative interface
• Consider disabling certificate management functionality until a patch is available if operationally feasible

Patch Information

At the time of publication, check the Endian Community Support portal for official security updates and patch availability. Organizations should apply vendor-provided patches as soon as they become available and verify that version 3.3.25 or earlier installations are upgraded to a fixed release.

Workarounds

• Deploy a web application firewall (WAF) in front of the Endian Firewall management interface configured to sanitize or block XSS payloads
• Implement strict Content-Security-Policy headers to prevent inline script execution: Content-Security-Policy: script-src 'self'; object-src 'none'
• Use browser isolation or dedicated administrative workstations for accessing the firewall management interface
• Implement multi-factor authentication for administrative access to reduce the risk of credential theft from XSS attacks

# Example WAF rule to block XSS in new_cert_name parameter (ModSecurity format)
SecRule ARGS:new_cert_name "@detectXSS" \
    "id:100001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'Potential XSS in certificate name parameter',\
    tag:'CVE-2026-34822'"