CVE-2026-1561 in WebSphere Application Server Liberty
Summary
by MITRE • 03/25/2026
IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.3 IBM WebSphere Application Server Liberty is vulnerable to server-side request forgery (SSRF). This may allow remote attacker to send unauthorized requests from the system, potentially leading to network enumeration or facilitating other attacks.
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Analysis
by VulDB Data Team • 05/28/2026
IBM WebSphere Application Server Liberty versions 17.0.0.3 through 26.0.0.3 contain a critical server-side request forgery vulnerability that enables remote attackers to forge requests from the affected system. This vulnerability falls under the CWE-918 category of Server-Side Request Forgery, which represents a significant security risk in web applications where user input is processed without proper validation. The flaw allows malicious actors to manipulate the application server into making unintended requests to internal or external systems, effectively bypassing normal network security controls.
The technical implementation of this vulnerability stems from insufficient validation of user-supplied input within the Liberty server's request handling mechanisms. When the application processes requests that include URLs or URI parameters, it fails to properly sanitize or validate these inputs before using them in outbound network communications. This creates an attack surface where an attacker can craft malicious requests that cause the server to connect to arbitrary destinations, potentially accessing internal network resources that should remain isolated from external access. The vulnerability is particularly dangerous because it can be exploited without authentication, allowing attackers to leverage the server's trusted network position to probe internal systems.
The operational impact of this vulnerability extends beyond simple network enumeration as it can facilitate more sophisticated attack vectors. An attacker who successfully exploits this SSRF vulnerability can potentially gain access to internal services, databases, or other systems that are normally protected by firewalls or network segmentation. The vulnerability can be used to perform internal port scanning, extract sensitive information from internal services, or even establish a pivot point for further attacks within the network infrastructure. This makes the vulnerability particularly dangerous in enterprise environments where network segmentation is critical for security posture maintenance and where the application server may have access to sensitive internal resources.
Organizations should immediately implement mitigations including input validation for all user-supplied URLs and URI parameters, network segmentation to limit outbound connectivity, and the deployment of web application firewalls to detect and block suspicious request patterns. The vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol: DNS and T1046 for network service scanning, highlighting the potential for both reconnaissance and lateral movement activities. Security teams should also consider implementing network monitoring solutions that can detect unusual outbound traffic patterns that may indicate exploitation attempts. Regular updates and patches should be applied immediately upon availability from IBM, as this vulnerability represents a high-severity risk that can be exploited remotely without requiring specialized tools or extensive knowledge of the target system.