CVE-2025-55737 is a medium-severity authorization bypass vulnerability affecting DogukanUrker's FlaskBlog application versions 2.8.0 and earlier. FlaskBlog is a blogging platform built using the Flask web framework. The vulnerability arises from improper authorization checks when deleting comments. Specifically, the application fails to validate whether the user requesting deletion actually owns the comment. This flaw exists in the code handling comment deletion in routes/post.py. An attacker can exploit this by intercepting the HTTP request to delete a comment and modifying the commentID parameter to target arbitrary comments belonging to other users. Because there is no ownership verification, the server processes the deletion request regardless of the requester's privileges or relationship to the comment. The CVSS 4.0 base score is 6.9, reflecting a network-exploitable vulnerability that requires no authentication or user interaction but results in a loss of integrity due to unauthorized comment deletions. The vulnerability is categorized under CWE-639 (Authorization Bypass Through User-Controlled Key), highlighting that the key used to identify the comment is user-controlled and unchecked. No known exploits are currently reported in the wild, and no patches have been linked yet. This vulnerability can be leveraged to disrupt the integrity of user-generated content on affected FlaskBlog instances, potentially undermining trust and user experience on the platform.

For European organizations using FlaskBlog as a blogging or content management solution, this vulnerability poses a risk to the integrity of their published content. Unauthorized deletion of comments can lead to loss of valuable user feedback, disruption of community discussions, and reputational damage. In regulated sectors such as media, education, or public services where content integrity and audit trails are critical, this could have compliance implications. Although the vulnerability does not directly expose sensitive data or enable privilege escalation, the ability to arbitrarily delete comments can be exploited for harassment, censorship, or misinformation by removing dissenting opinions or critical feedback. This could also indirectly affect availability if widespread abuse leads to service disruptions or user attrition. Since the vulnerability requires no authentication or user interaction, it can be exploited remotely by any attacker with network access to the application, increasing the risk profile for publicly accessible FlaskBlog deployments in Europe.

To mitigate CVE-2025-55737, organizations should implement strict authorization checks in the comment deletion workflow. Specifically, the server-side code must verify that the authenticated user owns the comment identified by the commentID before allowing deletion. This can be achieved by querying the comment's ownership in the database and comparing it against the current user's identity. Additionally, implementing role-based access control (RBAC) can help restrict deletion privileges to comment owners or designated moderators. Employing parameter validation and tamper-proofing mechanisms such as signed tokens or nonces for comment identifiers can reduce the risk of parameter manipulation. Organizations should monitor access logs for unusual deletion patterns and consider rate limiting deletion requests to mitigate abuse. Until an official patch is released, applying custom code fixes or disabling comment deletion functionality temporarily may be necessary. Regularly updating FlaskBlog to the latest secure versions once patches are available is essential. Finally, educating users about the vulnerability and encouraging reporting of suspicious activity can help detect exploitation attempts early.