CVE-2025-41075 in LimeSurvey
Summary
by MITRE • 11/20/2025
Vulnerability in LimeSurvey 6.13.0 in the endpoint /optin that causes infinite HTTP redirects when accessed directly. This behavior can be exploited to generate a Denegation of Service (DoS attack), by exhausting server or client resources. The system is unable to break the redirect loop, which can cause service degradation or browser instability.
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Analysis
by VulDB Data Team • 11/22/2025
The vulnerability identified as CVE-2025-41075 affects LimeSurvey version 6.13.0 and specifically targets the /optin endpoint within the application's web interface. This flaw represents a classic implementation error that creates an infinite redirect loop when the endpoint is accessed directly, fundamentally compromising the application's ability to process legitimate requests properly. The issue manifests as a denial of service condition that can severely impact system availability and user experience. From a cybersecurity perspective, this vulnerability demonstrates poor input validation and error handling mechanisms that fail to properly manage malformed or unexpected request patterns. The flaw exists in the application's routing logic where the system does not adequately check for redirect loops or implement proper termination conditions when processing requests to the optin endpoint. This type of vulnerability falls under CWE-617, which specifically addresses reachable assertion conditions and indicates a failure in the application's defensive programming practices. The vulnerability is particularly concerning because it can be exploited by any attacker who gains knowledge of the specific endpoint, making it accessible to both authenticated and unauthenticated threat actors. The infinite redirect behavior creates a cascading effect that consumes both server resources through continuous request processing and client resources through browser memory allocation and processing cycles. When a client browser encounters such a redirect loop, it typically attempts to resolve the redirection path by following each redirect instruction, leading to resource exhaustion and ultimately browser instability or complete crash.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader system reliability concerns. Servers processing these malformed requests will experience increased CPU utilization and memory consumption as they continuously attempt to resolve the redirect chain, potentially leading to resource starvation for legitimate users. The DoS condition can be amplified through automated scanning tools or bot networks that systematically probe the endpoint, causing sustained degradation of service availability. From a network infrastructure standpoint, this vulnerability can also impact load balancers and reverse proxies that may cache redirect responses or struggle to terminate the loop properly. The issue affects the application's availability and responsiveness, creating a scenario where legitimate users cannot access the optin functionality or potentially the entire LimeSurvey application if the redirect loop affects core routing mechanisms. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion, and represents a significant risk to business continuity and user experience.
Mitigation strategies for CVE-2025-41075 should focus on immediate patching of the LimeSurvey application to version 6.13.1 or later, which contains the necessary fixes to prevent infinite redirect loops in the /optin endpoint. Organizations should implement network-level protections such as rate limiting and request timeout configurations to prevent automated exploitation attempts and reduce the impact of successful attacks. Web application firewalls should be configured to detect and block suspicious redirect patterns or excessive redirect attempts to the optin endpoint. Additionally, monitoring solutions should be enhanced to detect unusual traffic patterns or resource consumption spikes that may indicate exploitation attempts. Application-level mitigations include implementing proper redirect validation logic that checks for circular redirect conditions and terminates loops after a predetermined number of redirects. The fix should incorporate proper error handling that prevents the system from entering infinite loops while maintaining the intended functionality of the optin endpoint. Security teams should also conduct thorough penetration testing to verify that all redirect paths within the application are properly validated and that no similar vulnerabilities exist in other endpoints. Configuration management practices should be enhanced to ensure that all instances of LimeSurvey are updated promptly and that proper change management procedures are followed to prevent similar issues from arising in the future. Organizations should also implement automated patch management processes to reduce the window of vulnerability exposure and ensure consistent security posture across all deployed instances.