CVE-2017-5475 in Serendipity
Summary
by MITRE
comment.php in Serendipity through 2.0.5 allows CSRF in deleting any comments.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2017-5475 affects Serendipity versions through 2.0.5 and represents a cross-site request forgery flaw in the comment.php script that enables unauthorized deletion of comments. This issue stems from the absence of proper anti-CSRF mechanisms within the comment deletion functionality, allowing malicious actors to craft crafted requests that can delete comments without proper authentication or authorization. The vulnerability specifically targets the comment management system where users can delete comments, but due to insufficient validation, any authenticated user or even unauthenticated attacker can manipulate the deletion process through forged requests. This weakness directly violates the principle of least privilege and proper access control enforcement.
The technical implementation of this vulnerability involves the comment.php script failing to validate the referer header or implement proper token-based authentication for deletion requests. When a user attempts to delete a comment, the system should verify that the request originates from a legitimate source within the application and that the user possesses proper authorization. Without these protections, an attacker can construct malicious web pages or emails containing embedded requests that automatically submit deletion commands to the vulnerable system. The flaw resides in the lack of CSRF tokens or referer validation that would normally prevent unauthorized requests from being processed. This vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses, and demonstrates the critical importance of implementing proper anti-CSRF measures in web applications.
The operational impact of this vulnerability extends beyond simple comment deletion, as it can be leveraged to disrupt content management systems, damage reputation, and potentially enable further attacks. An attacker could use this vulnerability to remove legitimate user comments, making it appear as though users are posting inappropriate content or that the system is malfunctioning. The ability to delete comments without authorization also creates opportunities for information tampering and can be combined with other attacks to create more significant security breaches. This vulnerability particularly affects content management systems where user-generated content is managed, as it undermines the integrity of the comment management process and can be exploited to manipulate public discourse or remove evidence of user interactions.
Mitigation strategies for this vulnerability require implementing robust anti-CSRF protection mechanisms within the comment deletion functionality. The most effective approach involves generating and validating unique CSRF tokens for each user session and ensuring that all deletion requests contain valid tokens before processing. Additionally, implementing proper referer header validation can provide an extra layer of protection against unauthorized requests. Organizations should also consider implementing rate limiting and monitoring for comment deletion activities to detect suspicious patterns. This vulnerability highlights the necessity of following security best practices outlined in the OWASP Top Ten and aligns with ATT&CK technique T1213, which covers data from information repositories, as it demonstrates how insufficient access controls can lead to unauthorized data manipulation. The fix should include comprehensive input validation and proper session management to ensure that only authorized users can perform comment deletion operations through legitimate interfaces.