CVE-2026-24323: BSP Applications XSS Vulnerability

CVE-2026-24323 Overview

CVE-2026-24323 is a URL Redirect vulnerability affecting SAP Business Server Pages (BSP) applications. The BSP applications allow an unauthenticated user to inject malicious script content via user-controlled URL parameters that are not sufficiently sanitized. When a victim accesses a crafted URL, the injected script is executed in the victim's browser, leading to a low impact on confidentiality and integrity, and no impact on the availability of the application.

Critical Impact

Unauthenticated attackers can craft malicious URLs to redirect victims to attacker-controlled domains or execute client-side scripts, potentially enabling phishing attacks, credential theft, or session hijacking through social engineering.

Affected Products

• SAP Business Server Pages (BSP) Applications
• SAP NetWeaver Application Server ABAP (hosting BSP applications)
• Organizations using custom BSP applications with URL parameter handling

Discovery Timeline

• February 10, 2026 - CVE-2026-24323 published to NVD
• February 10, 2026 - Last updated in NVD database

Technical Details for CVE-2026-24323

Vulnerability Analysis

This vulnerability is classified as CWE-601 (URL Redirection to Untrusted Site), commonly known as an "Open Redirect" vulnerability. The root cause lies in insufficient input validation and sanitization of user-controlled URL parameters within SAP BSP applications.

The vulnerability requires user interaction to exploit, as victims must click on a crafted malicious URL. Once clicked, the application processes the unsanitized URL parameters and either redirects the user to an attacker-specified location or executes injected script content within the context of the victim's browser session. The attack can be executed over the network by any unauthenticated user who can convince a victim to visit the malicious link.

While the direct impact on confidentiality and integrity is limited, this vulnerability is particularly dangerous when combined with social engineering tactics. Attackers can craft URLs that appear legitimate due to the trusted SAP domain, increasing the likelihood of successful phishing campaigns.

Root Cause

The vulnerability stems from improper input validation in the BSP application's URL parameter handling mechanism. The application fails to adequately sanitize or validate user-supplied input before using it in redirect operations or rendering it in the browser context. This allows attackers to inject arbitrary URLs or script content that bypasses the application's security controls.

Attack Vector

The attack leverages the network-accessible nature of BSP applications. An attacker constructs a malicious URL containing a crafted redirect parameter pointing to an attacker-controlled domain. The attacker then distributes this URL through phishing emails, malicious websites, or other social engineering channels.

When a victim clicks the link, they are initially directed to the legitimate SAP BSP application. However, due to the insufficient sanitization, the application processes the malicious parameter and redirects the victim to the attacker's site. This can be used to harvest credentials through fake login pages, distribute malware, or perform other malicious activities while leveraging the trust associated with the legitimate SAP domain.

The vulnerability can be exploited by crafting URLs with malicious redirect parameters that point to external domains. When processed by the vulnerable BSP application, these parameters are not properly validated, allowing the redirect to occur. See SAP Note #3678417 for specific technical details and affected components.

Detection Methods for CVE-2026-24323

Indicators of Compromise

• Unusual URL patterns in web server logs containing redirect parameters pointing to external domains
• HTTP requests to BSP applications with encoded or obfuscated URL parameters
• User complaints about being redirected to unexpected websites after clicking SAP-related links
• Phishing reports involving legitimate SAP domain URLs with suspicious query parameters

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests with suspicious redirect parameters
• Configure log analysis to identify requests containing external URLs in redirect-related parameters
• Deploy browser-based security tools to warn users about open redirect attempts
• Monitor for anomalous traffic patterns indicating exploitation attempts against BSP endpoints

Monitoring Recommendations

• Enable detailed logging for all BSP application URL parameter processing
• Set up alerts for requests containing URL-encoded characters in redirect parameters
• Monitor authentication system logs for credential compromise following potential phishing campaigns
• Implement user behavior analytics to detect accounts that may have been compromised through redirect attacks

How to Mitigate CVE-2026-24323

Immediate Actions Required

• Apply the security patch referenced in SAP Note #3678417 immediately
• Review and restrict access to affected BSP applications until patching is complete
• Alert users about potential phishing attempts using SAP-related URLs
• Implement network-level URL filtering to block known malicious redirect destinations

Patch Information

SAP has released a security patch addressing this vulnerability as part of their Security Patch Day program. Administrators should obtain the patch from SAP Note #3678417 and apply it according to SAP's recommended deployment procedures. The patch implements proper input validation and sanitization for URL parameters in BSP applications.

For complete patch details and the latest security updates, refer to the SAP Security Patch Day portal.

Workarounds

• Implement strict input validation at the application layer to whitelist allowed redirect destinations
• Configure web application firewalls to inspect and sanitize URL parameters before they reach BSP applications
• Disable or restrict access to BSP applications that handle redirect functionality until patching is feasible
• Educate users to verify the final destination URL before entering credentials after clicking any SAP-related links

# Example WAF rule to block suspicious redirect parameters
# Add to your web application firewall configuration
# Block requests containing redirect parameters with external URLs
SecRule ARGS "@rx (?i)(redirect|url|next|return|goto|link)=https?://(?!yourdomain\.com)" \
    "id:2026243231,phase:1,deny,status:403,msg:'Potential Open Redirect Attempt - CVE-2026-24323'"