CVE-2026-27246: Adobe Connect DOM-Based XSS Vulnerability

CVE-2026-27246 Overview

Adobe Connect versions 2025.3, 12.10 and earlier are affected by a DOM-based Cross-Site Scripting (XSS) vulnerability. An attacker could exploit this issue by manipulating the DOM environment to execute malicious JavaScript within the context of the victim's browser. Exploitation of this issue requires user interaction in that a victim must visit a crafted webpage. This vulnerability has a changed scope, meaning the impact extends beyond the vulnerable component itself.

Critical Impact

This DOM-based XSS vulnerability allows attackers to execute arbitrary JavaScript in the victim's browser with high confidentiality and integrity impact. The changed scope means compromised sessions could affect resources beyond Adobe Connect, potentially exposing sensitive meeting data, credentials, and enabling further attacks against connected systems.

Affected Products

• Adobe Connect version 2025.3 and earlier
• Adobe Connect version 12.10 and earlier
• Adobe Connect web client components

Discovery Timeline

• 2026-04-14 - CVE-2026-27246 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2026-27246

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically a DOM-based Cross-Site Scripting flaw. Unlike reflected or stored XSS attacks that involve server-side processing, DOM-based XSS occurs entirely within the client-side JavaScript execution environment.

In this case, Adobe Connect's client-side code processes user-controllable input and writes it to the DOM without proper sanitization or encoding. When a victim visits a maliciously crafted URL or webpage, the attacker-controlled data is processed by legitimate Adobe Connect JavaScript, resulting in the execution of arbitrary scripts within the user's authenticated browser session.

The changed scope designation indicates that successful exploitation can impact resources beyond the vulnerable Adobe Connect component. This could enable attackers to access data from other origins, hijack user sessions across different web applications, or leverage the compromised browser context for further attacks.

Root Cause

The root cause lies in improper handling of DOM manipulation operations within Adobe Connect's client-side JavaScript code. User-supplied input is being written to the Document Object Model without adequate validation, sanitization, or contextual output encoding. This allows attackers to inject executable JavaScript code through crafted input that bypasses the intended data handling.

Specifically, the vulnerability occurs when data from attacker-controllable sources (such as URL parameters, fragment identifiers, or document properties) flows into dangerous DOM manipulation sinks like innerHTML, document.write(), or dynamic script creation functions without proper sanitization.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker must craft a malicious webpage or URL containing the XSS payload and convince a victim to visit it. Attack scenarios include:

The attacker creates a specially crafted link containing malicious JavaScript in URL parameters or fragment identifiers. When a victim with an active Adobe Connect session clicks this link, the malicious script executes within their authenticated browser context. This could allow the attacker to steal session tokens, capture meeting credentials, exfiltrate sensitive conference data, or perform actions on behalf of the victim within Adobe Connect and potentially other applications sharing the same browser context.

Detection Methods for CVE-2026-27246

Indicators of Compromise

• Unusual URL patterns in web server logs containing JavaScript payloads targeting Adobe Connect endpoints
• Browser console errors indicating script injection attempts or Content Security Policy violations
• Unexpected outbound connections from client browsers during Adobe Connect sessions to unknown external domains
• User reports of unexpected behavior during or after joining Adobe Connect meetings via shared links

Detection Strategies

• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Deploy web application firewall (WAF) rules to identify and alert on XSS attack patterns in requests to Adobe Connect
• Monitor network traffic for suspicious JavaScript execution patterns and data exfiltration attempts during Adobe Connect usage
• Enable browser-based XSS auditing and logging where available

Monitoring Recommendations

• Review Adobe Connect access logs for unusual referrer patterns or malformed URL parameters
• Monitor for signs of session hijacking such as concurrent sessions from different geographic locations
• Implement real-time alerting for CSP violation reports from Adobe Connect deployments
• Track authentication anomalies that may indicate compromised session tokens

How to Mitigate CVE-2026-27246

Immediate Actions Required

• Update Adobe Connect to the latest patched version as specified in the Adobe security advisory
• Review and strengthen Content Security Policy headers to restrict inline script execution
• Educate users about the risks of clicking links to Adobe Connect from untrusted sources
• Implement strict URL validation and sanitization for any Adobe Connect links shared within your organization

Patch Information

Adobe has released a security update addressing this vulnerability. Detailed patch information is available in the Adobe Security Advisory APSB26-37. Organizations should prioritize applying this update given the critical severity and potential for session compromise.

Workarounds

• Deploy restrictive Content Security Policy headers including script-src 'self' to prevent execution of injected scripts
• Implement network-level filtering to block access to Adobe Connect from untrusted referrer sources
• Consider using a web application firewall to filter malicious XSS payloads in requests to Adobe Connect
• Restrict Adobe Connect access to trusted networks and authenticated users while awaiting patch deployment

# Example Content Security Policy header configuration for Apache
# Add to your Apache configuration or .htaccess file

Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';"
Header set X-XSS-Protection "1; mode=block"
Header set X-Content-Type-Options "nosniff"