CVE-2025-52892 in EspoCRM
Summary
by MITRE • 08/05/2025
EspoCRM is a web application with a frontend designed as a single-page application and a REST API backend written in PHP. In versions 9.1.6 and below, if a user loads Espo in the browser with double slashes (e.g https://domain//#Admin) and the webserver does not strip the double slash, it can cause a corrupted Slim router's cache. This will make the instance unusable until there is a completed rebuild. This is fixed in version 9.1.7.
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Analysis
by VulDB Data Team • 09/11/2025
CVE-2025-52892 represents a path traversal vulnerability affecting EspoCRM versions 9.1.6 and earlier, where improper handling of double slashes in URLs can lead to critical system corruption. The vulnerability exploits a weakness in the Slim framework's routing mechanism when processing malformed URLs containing consecutive forward slashes. When a user accesses the application with a URL containing double slashes such as https://domain//#Admin, and the webserver fails to normalize these paths, the Slim router's internal cache becomes corrupted. This corruption occurs because the routing component fails to properly sanitize or canonicalize the URL path before processing, allowing the malformed input to interfere with the routing cache structure. The issue stems from inadequate input validation at the application layer, specifically within the URL parsing and routing logic that does not account for malformed path sequences.
The technical impact of this vulnerability manifests as a complete service disruption requiring administrative intervention to restore system functionality. Once the Slim router cache becomes corrupted, the application enters an unusable state where subsequent requests fail to route properly through the system. The corruption affects the internal cache mechanism that stores routing information, causing the application to either crash or redirect requests to invalid endpoints. This type of vulnerability falls under CWE-22 Path Traversal and CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component, as it involves improper handling of input sequences that affect downstream processing components. The vulnerability directly impacts the application's availability and can be classified as a denial of service condition that requires manual cache clearing or complete system rebuild to resolve.
The operational implications extend beyond simple service disruption to include potential data accessibility issues and administrative overhead. System administrators must perform manual cache rebuilding procedures, which can be time-consuming and may require downtime during the recovery process. This vulnerability particularly affects environments where multiple users might access the application simultaneously, as the cache corruption can occur with any malformed URL request. The attack vector is relatively simple and can be exploited through basic browser navigation, making it accessible to both automated scanning tools and casual attackers. From an ATT&CK perspective, this vulnerability aligns with T1190 Exploit Public-Facing Application and T1499 Endpoint Denial of Service, as it enables attackers to disrupt service availability through manipulation of input parameters. Organizations running affected versions should prioritize immediate patching to prevent potential exploitation that could lead to extended service interruptions and operational disruptions.
The fix implemented in version 9.1.7 addresses the root cause by introducing proper URL path normalization and input validation within the Slim framework integration. This update ensures that double slash sequences are properly canonicalized before being processed by the routing component, preventing the corruption of internal cache structures. The patch demonstrates the importance of proper input sanitization in web applications and highlights the need for robust URL handling mechanisms in single-page applications that rely heavily on client-side routing. Organizations should implement comprehensive testing procedures to verify that URL normalization works correctly across different web server configurations and ensure that their monitoring systems can detect unusual routing behavior that might indicate cache corruption. The vulnerability serves as a reminder of how seemingly minor input handling issues can lead to major system failures and underscores the necessity of thorough security testing for all application components that process user-provided data.