CVE-2025-42873 in SAPUI5
Summary
by MITRE • 12/09/2025
SAPUI5 (and OpenUI5) packages use outdated 3rd party libraries with known security vulnerabilities. When markdown-it encounters special malformed input, it fails to terminate properly, resulting in an infinite loop. This Denial of Service via infinite loop causes high CPU usage and system unresponsiveness due to a blocked processing thread. This vulnerability has no impact on confidentiality or integrity but has a high impact on system availability.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/09/2025
SAPUI5 and OpenUI5 are widely used JavaScript frameworks for building enterprise web applications that rely heavily on third-party libraries to deliver enhanced functionality. These frameworks incorporate various open-source components including the markdown-it library which processes markdown content within user interfaces. The vulnerability arises from the improper handling of malformed input within this markdown processing component, creating a condition where the library enters an infinite loop during parsing operations. This specific flaw represents a classic denial of service vulnerability that operates at the application level rather than affecting network protocols or system-level components. The issue manifests when the markdown-it parser encounters specially crafted malformed input that causes it to repeatedly process the same data without proper termination conditions, effectively consuming CPU resources indefinitely.
The technical implementation of this vulnerability stems from inadequate input validation and error handling within the markdown-it library integration within SAPUI5 and OpenUI5 environments. When malformed markdown content is processed, the parser fails to detect and terminate the problematic parsing cycle, leading to thread blocking behavior that prevents other operations from executing. This infinite loop condition results in sustained high CPU utilization which can quickly overwhelm system resources and render the affected application unresponsive to legitimate user requests. The vulnerability operates at the software logic level and specifically targets the parsing mechanism of the markdown processor, making it particularly dangerous in enterprise environments where these frameworks power critical business applications. The flaw is classified under CWE-835 which specifically addresses infinite loops in software implementations, demonstrating how seemingly benign input processing can become a critical system failure point.
The operational impact of this vulnerability extends beyond simple system unresponsiveness to potentially disrupt entire business operations within organizations relying on SAPUI5 and OpenUI5 applications. High CPU usage caused by the infinite loop can lead to cascading failures where system resources become exhausted and legitimate user requests time out or fail to process. This denial of service condition affects system availability significantly, as users experience application downtime and administrators face challenges in identifying and resolving the root cause of performance degradation. The vulnerability's impact is particularly severe in production environments where continuous availability is critical for business operations. Organizations may experience service interruptions that affect customer interactions, data processing workflows, and overall system reliability, making this a high-priority security concern that requires immediate attention.
Mitigation strategies for this vulnerability should focus on updating the affected third-party libraries to versions that address the infinite loop condition in markdown-it processing. System administrators should implement input validation mechanisms that filter or sanitize markdown content before processing to prevent malicious inputs from triggering the vulnerable code paths. Additionally, monitoring solutions should be deployed to detect unusual CPU usage patterns that may indicate the presence of this vulnerability in active systems. Organizations should also consider implementing rate limiting and resource allocation controls to prevent a single processing thread from consuming excessive system resources. The remediation process should include comprehensive testing to ensure that updated libraries maintain application functionality while eliminating the vulnerability. This approach aligns with ATT&CK technique T1499.004 which addresses denial of service through resource exhaustion, emphasizing the need for proper resource management and input validation to prevent such attacks from compromising system availability.