CVE-2025-55737 in FlaskBlog
Summary
by MITRE • 08/19/2025
flaskBlog is a blog app built with Flask. In 2.8.0 and earlier, when deleting a comment, there's no validation of the ownership of the comment. Every user can delete an arbitrary comment of another user on every post, by simply intercepting the delete request and changing the commentID. The code that causes the problem is in routes/post.py.
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Analysis
by VulDB Data Team • 08/19/2025
The vulnerability identified as CVE-2025-55737 represents a critical access control flaw within the flaskBlog application framework version 2.8.0 and earlier. This security weakness stems from insufficient input validation and authentication checks during the comment deletion process, creating a scenario where any authenticated user can manipulate HTTP requests to remove comments authored by other users. The vulnerability specifically resides in the routes/post.py file, which handles the comment deletion functionality without proper authorization verification. This type of flaw falls under the CWE-862 weakness category, which defines insufficient authorization as a fundamental security issue where the system fails to properly verify that an actor is authorized to perform a requested operation. The application's architecture lacks proper ownership validation mechanisms, allowing attackers to exploit the predictable nature of comment identifiers to execute unauthorized deletions across the platform.
The technical implementation of this vulnerability enables attackers to perform unauthorized comment removal through simple request interception and modification techniques. When a user attempts to delete a comment, the application relies solely on the comment identifier provided in the request without verifying whether the requesting user owns or has authorization to modify that specific comment. This creates a privilege escalation scenario where users can manipulate the commentID parameter in the delete request to target comments belonging to other users. The flaw demonstrates a classic case of insecure direct object reference vulnerability, where the application exposes internal object references to users without proper access control checks. According to ATT&CK framework, this vulnerability maps to T1078 Privilege Escalation and T1566 Credential Access techniques, as it allows unauthorized users to operate with elevated privileges through manipulation of existing user permissions.
The operational impact of this vulnerability extends beyond simple data manipulation, potentially enabling more severe consequences within the blog application's ecosystem. Attackers could use this weakness to remove critical comments, disrupt discussions, or even eliminate evidence of user interactions that might be important for community moderation. The vulnerability affects all users of the application who have authenticated access, making it particularly dangerous in environments where multiple users interact with shared content. The scope of potential damage includes undermining community trust, compromising content integrity, and potentially enabling further attacks through the manipulation of user-generated content. From a security perspective, this vulnerability represents a failure in the principle of least privilege, where the application does not enforce proper access controls to ensure that users can only modify resources they own or have explicit authorization to manage.
Mitigation strategies for CVE-2025-55737 require immediate implementation of proper authorization checks within the comment deletion functionality. The application must validate that the authenticated user requesting comment deletion is the actual owner of that comment before executing the deletion operation. This can be achieved through database queries that verify user ownership or by implementing proper session management and access control lists. The fix should involve modifying the routes/post.py file to include ownership verification logic that compares the requesting user's identifier with the comment's author identifier before proceeding with deletion. Security measures should also include input validation of all request parameters and logging of deletion attempts for audit purposes. Organizations should implement proper code review processes and security testing to prevent similar issues in future releases, ensuring that all user-facing operations include appropriate authorization checks. Additionally, the application should be updated to version 2.8.1 or later where this vulnerability has been addressed through proper access control implementation.