CVE-2026-73155 in cti-transmute
Summary
by MITRE • 08/11/2026
Affected versions of cti-transmute allow authenticated users to add or remove emoji reactions on comments without first checking whether those users are authorized to view the target comment.
The vulnerable react() handler passed an attacker-controlled comment_id directly to comments_repo.toggle_reaction() after only validating that the ID existed syntactically and that the requested emoji was permitted. Because comment-level visibility was not enforced, a user who could identify the ID of a private or otherwise inaccessible comment could modify reaction state on that comment despite lacking permission to access it.
The fix retrieves the target comment, rejects missing or deleted comments, retrieves its associated conversion, and enforces access.can_see_comment(current_user, comment, conversion). Unauthorized requests now receive HTTP 403.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical authorization bypass in the cti-transmute application's comment reaction functionality. The flaw exists within the react() handler implementation where the system fails to perform proper access control checks before allowing users to modify comment reactions. The vulnerability stems from the improper handling of user permissions during emoji reaction operations, creating an avenue for unauthorized access to private content through manipulation of comment identifiers.
The technical implementation contains a fundamental security oversight where the application validates only syntactic correctness of the comment_id parameter and verifies that the requested emoji is permitted in the system. However, it completely omits checks to ensure that the authenticated user has proper authorization to view or interact with the target comment. This failure allows attackers to exploit knowledge of valid comment identifiers to manipulate reaction states on comments they should not be able to access. The vulnerability directly aligns with CWE-674, which addresses unauthorized modification of data through improper access control enforcement.
The operational impact of this vulnerability is significant as it enables users to manipulate reaction data on private or restricted comments without proper authorization. Attackers can identify comment identifiers for protected content and then modify reaction states, potentially leading to information disclosure through indirect means. This type of vulnerability can be particularly dangerous in collaborative environments where comment reactions might contain sensitive metadata about content relationships or user interactions. The attack pattern follows principles described in the ATT&CK framework under privilege escalation and data manipulation techniques.
The mitigation implemented addresses the core issue by enforcing proper access control checks before any reaction modification occurs. The fix requires retrieving the target comment object, validating its existence and non-deletion status, and then performing a comprehensive permission check using access.can_see_comment() function that evaluates whether the current user has appropriate authorization to view the specific comment within its associated conversion context. This approach aligns with the principle of least privilege by ensuring that all operations on protected resources require proper authorization before execution. The implementation now returns HTTP 403 Forbidden responses for unauthorized access attempts, providing clear feedback to attackers while maintaining system integrity.
The solution demonstrates proper defensive programming practices by implementing a layered access control mechanism that validates both resource existence and user permissions before allowing any modification operations. This approach prevents the type of information leakage that could occur through reaction manipulation on restricted content, ensuring that comment reaction functionality respects the application's access control policies. The fix also reinforces the principle that all external inputs must be validated for both correctness and authorization context before processing, which is essential for maintaining secure application behavior in multi-user environments where privilege levels vary significantly.