CVE-2025-43567: Adobe Connect XSS Vulnerability

CVE-2025-43567 Overview

Adobe Connect versions 12.8 and earlier are affected by a reflected Cross-Site Scripting (XSS) vulnerability that could be abused by an attacker to inject malicious scripts into vulnerable form fields. Malicious JavaScript may be executed in a victim's browser when they browse to the page containing the vulnerable field. A successful attacker can abuse this to achieve session takeover, increasing the confidentiality and integrity impact as high.

Critical Impact

This reflected XSS vulnerability enables attackers to execute arbitrary JavaScript in victim browsers, potentially leading to session hijacking, credential theft, and unauthorized access to Adobe Connect meetings and content.

Affected Products

• Adobe Connect versions 12.8 and earlier

Discovery Timeline

• 2025-05-13 - CVE-2025-43567 published to NVD
• 2025-05-19 - Last updated in NVD database

Technical Details for CVE-2025-43567

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The reflected XSS flaw exists within Adobe Connect's form field handling mechanisms, where user-supplied input is not properly sanitized before being rendered in the browser.

The vulnerability requires user interaction, as victims must navigate to a maliciously crafted URL or page containing the vulnerable field. Once triggered, the injected script executes within the context of the victim's authenticated session, enabling attackers to perform actions on behalf of the user.

The scope is changed (S:C in the CVSS vector), meaning the vulnerable component and impacted component are different - the vulnerability exists in Adobe Connect's server-side processing, but the impact occurs in the victim's browser environment. This cross-boundary impact significantly elevates the risk profile.

Root Cause

The root cause stems from inadequate input validation and output encoding in Adobe Connect's form field processing. When user-controlled data is reflected back to the browser without proper sanitization, it allows attackers to inject executable script content. The application fails to implement appropriate encoding for the output context, enabling the browser to interpret malicious payloads as legitimate script code rather than inert data.

Attack Vector

The attack vector is network-based, requiring an attacker to craft a malicious URL or web page that exploits the vulnerable form field. The attack flow typically involves:

1. Attacker identifies the vulnerable form field in Adobe Connect
2. Attacker crafts a URL containing malicious JavaScript payload targeting that field
3. Attacker delivers the malicious URL to victims via phishing emails, social engineering, or compromised websites
4. Victim clicks the link while authenticated to Adobe Connect
5. The malicious script executes in the victim's browser context
6. Attacker achieves session takeover, capturing session tokens or performing unauthorized actions

The vulnerability does not require any privileges on the target system, making it exploitable by unauthenticated attackers against any Adobe Connect user.

Detection Methods for CVE-2025-43567

Indicators of Compromise

• Unusual URL parameters containing JavaScript code or encoded script tags in Adobe Connect access logs
• Client-side errors or anomalous script execution detected in browser developer tools during Adobe Connect sessions
• Reports from users of unexpected behavior or redirects when accessing Adobe Connect meeting links
• Session tokens appearing in unexpected locations or being transmitted to external domains

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block common XSS patterns in request parameters
• Monitor Adobe Connect server logs for requests containing suspicious encoded characters or script injection patterns
• Deploy Content Security Policy (CSP) headers to detect and report inline script execution attempts
• Enable browser-based XSS auditing and monitor for triggered protections

Monitoring Recommendations

• Review Adobe Connect access logs for unusual query string patterns containing <script>, javascript:, onerror=, or encoded variants
• Monitor for spikes in session invalidation or authentication failures that may indicate session hijacking attempts
• Implement network-level monitoring for data exfiltration patterns from Adobe Connect sessions
• Track user reports of phishing attempts leveraging Adobe Connect URLs

How to Mitigate CVE-2025-43567

Immediate Actions Required

• Upgrade Adobe Connect to a patched version as specified in the Adobe Security Advisory APSB25-36
• Review and validate any custom integrations or plugins that interact with Adobe Connect form fields
• Implement Content Security Policy headers to restrict inline script execution
• Educate users about the risks of clicking untrusted links, especially those pointing to Adobe Connect resources

Patch Information

Adobe has released a security update addressing this vulnerability in security bulletin APSB25-36. Organizations should immediately apply the latest Adobe Connect update available through their Adobe licensing portal. The patch addresses the reflected XSS vulnerability by implementing proper input validation and output encoding for affected form fields.

For detailed patch information and download links, refer to the Adobe Security Advisory APSB25-36.

Workarounds

• Deploy a Web Application Firewall (WAF) with XSS filtering rules in front of Adobe Connect instances as a temporary mitigation
• Implement strict Content Security Policy (CSP) headers to prevent execution of injected scripts: Content-Security-Policy: script-src 'self'; object-src 'none'
• Consider restricting access to Adobe Connect to trusted networks or VPN users until patching is complete
• Enable HTTP-only and Secure flags on session cookies to reduce session hijacking risk

# Example WAF rule for ModSecurity to block common XSS patterns
SecRule ARGS "@rx (?i)<script[^>]*>|javascript:|on\w+\s*=" \
    "id:100001,phase:2,deny,status:403,msg:'Potential XSS attack blocked'"