CVE-2025-2274: Forcepoint Web Security Stored XSS Flaw

CVE-2025-2274 Overview

CVE-2025-2274 is a Stored Cross-Site Scripting (XSS) vulnerability affecting Forcepoint Web Security (On-Prem) on Windows platforms. The vulnerability stems from improper neutralization of input during web page generation (CWE-79), allowing attackers to inject and persist malicious scripts within the application.

Stored XSS vulnerabilities are particularly dangerous because the malicious payload persists within the application's data store. When other users access the affected page, the injected script executes in their browser context, potentially leading to session hijacking, credential theft, or further compromise of the web security infrastructure.

Critical Impact

Attackers with adjacent network access can inject persistent malicious scripts that execute in the browsers of other users accessing the Forcepoint Web Security management interface, potentially compromising administrative sessions.

Affected Products

• Forcepoint Web Security (On-Prem) through version 8.5.6
• Windows-based deployments of Forcepoint Web Security

Discovery Timeline

• 2026-03-16 - CVE-2025-2274 published to NVD
• 2026-03-17 - Last updated in NVD database

Technical Details for CVE-2025-2274

Vulnerability Analysis

This vulnerability affects the input handling mechanisms within Forcepoint Web Security's on-premises deployment on Windows systems. The application fails to properly sanitize user-supplied input before incorporating it into dynamically generated web pages, creating a Stored XSS condition.

When malicious input containing JavaScript or HTML code is submitted to the vulnerable component, it is stored in the application's backend without adequate sanitization. Subsequently, when this stored data is rendered in the web interface for other users (including administrators), the malicious script executes within their browser session.

The adjacent network attack vector indicates that exploitation requires the attacker to have network proximity to the target system, such as being on the same local network segment, shared cloud infrastructure, or VPN connection. User interaction is required for successful exploitation, as a victim must view the page containing the injected payload.

Root Cause

The root cause is inadequate input validation and output encoding within Forcepoint Web Security's web interface components. Specifically, the application does not properly neutralize special characters and script content before storing user input or when rendering stored data back to the user interface. This violates the security principle of treating all user input as untrusted and encoding output appropriately for the rendering context.

Attack Vector

The attack requires adjacent network access to the Forcepoint Web Security on-premises installation. An attacker would identify input fields or parameters that are stored by the application and subsequently displayed to other users. By crafting input containing malicious JavaScript, the attacker can inject persistent payloads that execute whenever other users view the affected content.

Typical attack scenarios include injecting scripts into configuration fields, log entries, user profile data, or other stored content that is rendered in the management interface. When administrators or other users access pages displaying this data, the malicious script executes with their session privileges.

For technical details on the vulnerability mechanism, refer to the Forcepoint Security Advisory.

Detection Methods for CVE-2025-2274

Indicators of Compromise

• Unusual JavaScript code or HTML tags present in stored configuration data or user-submitted fields
• Browser developer console errors indicating cross-origin requests or script execution from unexpected sources
• Administrative session anomalies such as unexpected actions performed under legitimate user accounts
• Network traffic patterns showing data exfiltration or communication with external domains from administrative workstations

Detection Strategies

• Implement Content Security Policy (CSP) headers and monitor for violations indicating XSS attempts
• Review web server and application logs for input containing script tags, event handlers, or encoded JavaScript payloads
• Deploy web application firewall (WAF) rules to detect and block common XSS patterns in requests to the Forcepoint management interface
• Monitor for anomalous administrative account activity that may indicate session compromise

Monitoring Recommendations

• Enable detailed logging on the Forcepoint Web Security management interface to capture all user input and configuration changes
• Implement security information and event management (SIEM) correlation rules to detect potential XSS exploitation patterns
• Monitor browser-based endpoint protection alerts for script injection or suspicious web activity originating from the management console
• Regularly audit stored data fields for the presence of suspicious HTML or JavaScript content

How to Mitigate CVE-2025-2274

Immediate Actions Required

• Update Forcepoint Web Security (On-Prem) to a version beyond 8.5.6 that addresses this vulnerability
• Restrict network access to the Forcepoint Web Security management interface to trusted administrative networks only
• Implement strong Content Security Policy headers to mitigate XSS impact
• Review all stored data for evidence of injected malicious content and sanitize affected records

Patch Information

Forcepoint has released a security advisory addressing this Stored XSS vulnerability. Administrators should consult the Forcepoint Security Advisory for official patch information and update their installations to the latest available version that remediates CVE-2025-2274.

Organizations running Forcepoint Web Security through version 8.5.6 should prioritize applying the vendor-provided update to eliminate this vulnerability.

Workarounds

• Limit access to the Forcepoint Web Security management interface to a minimal set of trusted administrators from dedicated management workstations
• Deploy a web application firewall (WAF) in front of the management interface configured with XSS detection and prevention rules
• Implement network segmentation to ensure the management interface is only accessible from isolated administrative network segments
• Use browser extensions or endpoint protection solutions that provide XSS filtering capabilities for administrative users accessing the interface

# Example: Restrict management interface access via firewall rules
# Allow access only from trusted administrative subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP