CVE-2025-55737 Overview
CVE-2025-55737 is an Insecure Direct Object Reference (IDOR) vulnerability [CWE-639] in flaskBlog, an open-source blog application built with Flask by developer dogukanurker. The flaw affects versions 2.8.0 and earlier. When a user deletes a comment, the application fails to verify that the requester owns the target comment. An attacker can intercept the delete request and modify the commentID parameter to remove any comment on any post. The vulnerable code resides in routes/post.py. Exploitation requires no authentication bypass beyond having a standard user account and can be performed over the network with low complexity.
Critical Impact
Any authenticated user can delete arbitrary comments belonging to other users across all posts, resulting in loss of user-generated content integrity.
Affected Products
- dogukanurker flaskBlog version 2.8.0
- dogukanurker flaskBlog all prior releases
- Deployments using the vulnerable routes/post.py comment deletion handler
Discovery Timeline
- 2025-08-19 - CVE-2025-55737 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-55737
Vulnerability Analysis
The vulnerability is a Broken Object Level Authorization flaw classified under [CWE-639]: Authorization Bypass Through User-Controlled Key. The comment deletion route in routes/post.py accepts a commentID value from the client and performs the deletion against the database without verifying that the authenticated session owns the targeted comment. Because the identifier is a predictable integer or resource key, attackers enumerate values or observe them in rendered pages. The impact is limited to integrity of comment data, with no direct effect on confidentiality or availability of the underlying host.
Root Cause
The delete handler trusts the client-supplied commentID as the sole determinant of which record to remove. Missing checks compare the comment's stored authorID against the current session user. Similarly, the handler does not restrict deletion to users with elevated roles such as post owners or administrators. This is a classic authorization gap in which authentication is enforced while object-level authorization is not.
Attack Vector
Exploitation is straightforward. An authenticated flaskBlog user issues a legitimate deletion request against a comment they own, intercepts the HTTP request using a proxy such as Burp Suite or mitmproxy, and substitutes the commentID value with the identifier of a target comment belonging to another user. The server processes the request and removes the target comment. No specialized tooling, memory corruption primitives, or authentication bypass is required. See the GitHub Security Advisory for repository-specific technical detail.
Detection Methods for CVE-2025-55737
Indicators of Compromise
- Unexpected comment deletion events in application logs where the requesting user does not match the comment's stored author.
- Repeated HTTP POST or DELETE requests to the comment deletion endpoint with incrementing or enumerated commentID values from a single session.
- User support reports of comments disappearing without owner action.
Detection Strategies
- Instrument the comment deletion route to log the session user identifier alongside the target commentID and the stored comment author. Alert when these values diverge.
- Deploy web application firewall rules that flag rapid sequential requests to the deletion endpoint from a single authenticated session.
- Correlate database DELETE operations against the comments table with the originating web request user context.
Monitoring Recommendations
- Retain HTTP access logs including request bodies for the comment deletion route for forensic review.
- Baseline normal comment deletion rates per user and alert on statistical outliers.
- Review Flask session logs and reverse proxy logs for enumeration patterns targeting commentID parameters.
How to Mitigate CVE-2025-55737
Immediate Actions Required
- Upgrade flaskBlog to a version released after 2.8.0 that contains the ownership validation fix, once available from the upstream repository.
- Audit the comments database for recently deleted records and restore from backup if unauthorized deletions are identified.
- Apply an interim patch to routes/post.py that verifies the current session user owns the target comment or holds administrative privilege before executing the delete.
Patch Information
Refer to the GitHub Security Advisory GHSA-6hp9-jv2f-88wr for the maintainer's remediation guidance. The corrective change requires adding an authorization check in the comment deletion handler in routes/post.py that compares the session user identifier against the comment's stored author identifier before invoking the database delete operation.
Workarounds
- Disable the comment deletion feature at the route level until the ownership check is implemented.
- Restrict comment deletion to administrative accounts by adding a role check in the route decorator.
- Place the application behind a reverse proxy rule that blocks requests to the comment deletion endpoint from non-administrative sessions.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
