CVE-2026-0505 Overview
CVE-2026-0505 is an Open Redirect vulnerability affecting SAP Business Server Pages (BSP) applications. The vulnerability allows an unauthenticated user to manipulate user-controlled URL parameters that are not sufficiently validated. This insufficient input validation could result in unvalidated redirection to attacker-controlled websites, potentially facilitating phishing attacks and credential theft.
Critical Impact
Unauthenticated attackers can redirect users to malicious websites by manipulating URL parameters in BSP applications, enabling phishing and social engineering attacks.
Affected Products
- SAP Business Server Pages (BSP) applications
- SAP NetWeaver-based systems with BSP functionality
Discovery Timeline
- February 10, 2026 - CVE-2026-0505 published to NVD
- February 10, 2026 - Last updated in NVD database
Technical Details for CVE-2026-0505
Vulnerability Analysis
This vulnerability stems from inadequate validation of URL parameters within SAP BSP applications. When user-supplied URL parameters are processed by the application, they are not properly sanitized or validated against a whitelist of trusted domains. As a result, attackers can craft malicious URLs that redirect unsuspecting users to external, attacker-controlled websites.
The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), though the primary attack vector is open redirect functionality. The network-based attack requires user interaction, as victims must click on a crafted malicious link. The scope is changed, meaning the vulnerable component impacts resources beyond its security scope.
Root Cause
The root cause of CVE-2026-0505 lies in the insufficient validation of user-controlled URL parameters within BSP applications. The application fails to implement proper input validation mechanisms such as:
- Whitelist validation for redirect destinations
- Proper URL parsing and domain verification
- Rejection of external or untrusted redirect targets
This allows attackers to inject arbitrary URLs into redirect parameters, bypassing any existing security controls.
Attack Vector
The attack leverages the network-accessible nature of BSP applications. An attacker crafts a URL containing a malicious redirect parameter pointing to a phishing site or malware distribution page. The attacker then distributes this crafted URL through phishing emails, social media, or other channels.
When a victim clicks the link, they initially connect to the legitimate SAP application, which builds trust. The application then redirects the user to the attacker-controlled destination without proper validation. Because the initial URL appears legitimate, users are more likely to trust the final destination, making phishing attacks more effective.
The vulnerability requires user interaction (clicking the malicious link) but no authentication to exploit, making it accessible to any external attacker who can reach the BSP application.
Detection Methods for CVE-2026-0505
Indicators of Compromise
- HTTP requests to BSP applications containing external URLs in redirect parameters
- Unusual redirect parameter values pointing to non-corporate domains
- Log entries showing user sessions redirecting to unexpected external destinations
- Phishing reports from users who clicked links that initially appeared to be legitimate SAP URLs
Detection Strategies
- Monitor web application logs for redirect parameters containing external domains
- Implement Web Application Firewall (WAF) rules to detect and block suspicious redirect patterns
- Configure SIEM alerts for outbound redirects from BSP applications to untrusted destinations
- Review URL parameter patterns in HTTP access logs for anomalous redirect targets
Monitoring Recommendations
- Enable detailed logging for all BSP application URL parameters
- Set up real-time alerting for redirect requests to domains outside the corporate whitelist
- Conduct periodic log analysis to identify potential exploitation attempts
- Monitor for phishing reports that reference URLs containing your organization's BSP application domains
How to Mitigate CVE-2026-0505
Immediate Actions Required
- Apply the security patch referenced in SAP Note #3678417
- Review and restrict access to affected BSP applications where possible
- Implement WAF rules to block requests with external URLs in redirect parameters
- Educate users about the risks of clicking links, even those appearing to point to internal systems
Patch Information
SAP has released security patches addressing this vulnerability. Organizations should consult the SAP Security Patch Day portal and apply the fix referenced in SAP Note #3678417. The patch implements proper URL validation to ensure redirect destinations are limited to trusted domains.
Workarounds
- Configure WAF rules to strip or validate redirect parameters in requests to BSP applications
- Implement network-level restrictions to limit access to BSP applications from trusted networks only
- Deploy URL filtering at the proxy level to block redirects to known malicious domains
- Consider disabling redirect functionality in BSP applications if not required for business operations
# Example WAF rule to block external redirects (pseudo-configuration)
# Block requests where redirect parameter contains external domains
# Adjust patterns based on your organization's trusted domain list
SecRule ARGS:redirect "!@beginsWith https://your-trusted-domain.com" "id:10001,phase:1,deny,status:403,msg:'Blocked potential open redirect'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
