CVE-2026-73155 MISP CVE debrief

Who should care

Users of cti-transmute, administrators of comment-based systems, security teams monitoring for potential authorization bypass vulnerabilities, and operators of platforms using cti-transmute should be aware of this vulnerability and take necessary precautions to protect their systems and data. This includes verifying and enforcing proper authorization checks for comment reactions, restricting access to sensitive comments based on user permissions, and monitoring and auditing comment reaction modifications for suspicious activity. Additionally, implementing additional security measures to prevent unauthorized access to private comments is recommended. Those responsible for vulnerability management and incident response should prioritize patching or mitigating this vulnerability to prevent potential exploitation. Security teams should also review compensating controls for exposed systems while remediation is scheduled and verified, and track exceptions, retest remediated assets, and close the item only after evidence is documented. IT asset inventory managers should verify that affected product deployments exist in managed environments and assign an owner for follow-up. Those involved in source tracking and monitoring should check relevant monitoring, detection, and logs for exposed assets that need extra review. Those responsible for change management should plan vendor-supported updates or mitigations through normal change control where exposure is confirmed. Those responsible for rollback and change windows should consider the potential impact of this vulnerability on their systems and plan accordingly. Those involved in exposure review should assess the potential impact of this vulnerability on their systems and prioritize remediation efforts accordingly. Those responsible for compensating controls should review and implement additional security measures to prevent unauthorized access to private comments. Those involved in vendor patch guidance should verify and enforce proper authorization checks for comment reactions and restrict access to sensitive comments based on user permissions. Those responsible for monitoring and asset inventory should prioritize this

Technical summary

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 fix retrieves the target comment, rejects missing or deleted comments, retrieves its associated conversion, and enforces access.can_see_comment(current_user, comment, conversion). This ensures that users can only modify reaction state on comments they are permitted to access.

Defensive priority

Authenticated users could modify reaction state on private or inaccessible comments despite lacking permission to access them, allowing potential unauthorized access to sensitive information.

Recommended defensive actions

• Verify and enforce proper authorization checks for comment reactions
• Restrict access to sensitive comments based on user permissions
• Monitor and audit comment reaction modifications for suspicious activity
• Implement additional security measures to prevent unauthorized access to private comments
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

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.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.