CVE-2025-49553: Adobe Connect DOM-Based XSS Vulnerability

CVE-2025-49553 Overview

Adobe Connect versions 12.9 and earlier are affected by a DOM-based Cross-Site Scripting (XSS) vulnerability that could be exploited by an attacker to execute malicious scripts in a victim's browser. Exploitation of this issue requires user interaction in that a victim must navigate to a crafted web page. A successful attacker can abuse this to achieve session takeover, increasing the confidentiality and integrity impact as high.

Critical Impact

This DOM-based XSS vulnerability enables session takeover attacks with high confidentiality and integrity impact. The scope is changed, meaning attacks can affect resources beyond the vulnerable component.

Affected Products

• Adobe Connect versions 12.9 and earlier
• Deployments on Microsoft Windows
• Deployments on Apple macOS

Discovery Timeline

• October 14, 2025 - CVE-2025-49553 published to NVD
• October 17, 2025 - Last updated in NVD database

Technical Details for CVE-2025-49553

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically manifesting as a DOM-based Cross-Site Scripting flaw. Unlike reflected or stored XSS variants, DOM-based XSS occurs entirely within the client-side JavaScript execution context when the application writes user-controllable data to the Document Object Model without proper sanitization.

In Adobe Connect, the vulnerable code path processes URL parameters or other client-side inputs and dynamically renders them into the page DOM. Because the malicious payload is executed within the victim's browser session, an attacker who successfully exploits this vulnerability can hijack authenticated user sessions, potentially gaining access to meeting rooms, recordings, and administrative functions depending on the victim's privileges.

The changed scope designation indicates that exploitation of this vulnerability can impact resources beyond the Adobe Connect application itself, such as other web origins or browser contexts.

Root Cause

The root cause stems from improper handling of user-supplied input within client-side JavaScript code. The application fails to adequately sanitize or encode data before inserting it into the DOM, allowing specially crafted input containing JavaScript payloads to be interpreted and executed as code rather than rendered as inert content.

DOM-based XSS vulnerabilities typically arise from unsafe usage of JavaScript methods such as document.write(), innerHTML, outerHTML, or direct DOM manipulation APIs that process untrusted data from sources like document.URL, document.location, window.name, or URL fragment identifiers.

Attack Vector

The attack requires user interaction where a victim must navigate to a maliciously crafted URL. An attacker would construct a link to the Adobe Connect instance containing an XSS payload embedded within URL parameters or fragments. When the victim clicks this link and their browser processes the page, the vulnerable JavaScript code reads the malicious input and writes it to the DOM, triggering script execution within the victim's browser context.

Because the payload executes within an authenticated session, the attacker can steal session tokens, perform actions on behalf of the user, or redirect sensitive data to attacker-controlled infrastructure. This network-based attack vector requires no prior authentication or special privileges from the attacker.

Detection Methods for CVE-2025-49553

Indicators of Compromise

• Unusual URL patterns containing JavaScript code in query parameters or hash fragments directed at Adobe Connect instances
• Web server logs showing requests with encoded script tags (%3Cscript%3E) or event handlers (onerror, onload) in URL parameters
• Client-side error logs indicating unexpected script execution or DOM manipulation errors
• Session anomalies such as multiple geographic locations for the same session token

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block common XSS payload patterns in requests to Adobe Connect
• Monitor browser console logs and client-side telemetry for unexpected script execution events
• Deploy Content Security Policy (CSP) violation reporting to identify attempted XSS attacks
• Analyze web traffic for suspicious URL patterns containing encoded special characters commonly used in XSS payloads

Monitoring Recommendations

• Enable detailed access logging on Adobe Connect servers and review for requests containing suspicious URL parameters
• Configure Security Information and Event Management (SIEM) alerts for patterns indicative of XSS exploitation attempts
• Monitor for anomalous session behavior that could indicate session hijacking following successful exploitation
• Implement real-time alerting for CSP violations reported from Adobe Connect web clients

How to Mitigate CVE-2025-49553

Immediate Actions Required

• Upgrade Adobe Connect to the latest patched version as recommended in Adobe Security Advisory APSB25-70
• Review and restrict access to Adobe Connect instances to trusted users until patching is complete
• Implement strict Content Security Policy headers to mitigate the impact of potential XSS exploitation
• Educate users about the risks of clicking suspicious links, particularly those directing to Adobe Connect meeting URLs

Patch Information

Adobe has released security updates to address this vulnerability. Organizations should apply the patches detailed in Adobe Security Advisory APSB25-70. The advisory provides version-specific remediation guidance for affected Adobe Connect deployments on both Windows and macOS platforms.

Workarounds

• Deploy a Web Application Firewall with rules specifically designed to detect and block XSS payload patterns targeting Adobe Connect
• Implement restrictive Content Security Policy headers including script-src 'self' to prevent inline script execution
• Consider network segmentation to limit exposure of Adobe Connect instances to trusted network zones
• Enable browser-level XSS protection features and encourage use of modern browsers with enhanced security controls

# Example CSP header configuration for Apache
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'self';"