CVE-2026-57574 misskey-dev CVE debrief

Who should care

Administrators and users of the Misskey social media platform should be aware of this vulnerability and take necessary actions to protect their accounts and systems. Additionally, security teams should prioritize and coordinate response efforts based on the vulnerability's severity and potential impact on the organization. Affected administrators should review and update their systems as soon as possible to prevent potential exploitation. Users should educate themselves about the importance of securing TOTP codes and consider implementing additional authentication factors.

Technical summary

The vulnerability exists in the UserAuthService of Misskey, where insufficient validation of used TOTP tokens allows for code reuse within its valid time step. This issue can be exploited if an attacker obtains both user credentials and a TOTP code concurrently. The vulnerability's technical details and defensive impact should be understood and communicated to relevant stakeholders to ensure effective mitigation and response. Compensating controls, such as IP restrictions or behavioral monitoring, may be necessary for exposed systems while remediation is scheduled and verified.

Defensive priority

High priority should be given to updating Misskey to version 2026.6.0 or later. Users should also be cautious about concurrent access to their accounts and TOTP codes. Additional monitoring for concurrent access attempts should be implemented. Users should educate themselves about the importance of securing TOTP codes and consider implementing additional authentication factors. Affected administrators should review and update their systems as soon as possible to prevent potential exploitation. Compensating controls, such as IP restrictions or behavioral monitoring, may be necessary for exposed systems while remediation is scheduled and verified. Exceptions and retesting of remediated assets should be tracked, and the item should only be closed after evidence of successful remediation is documented. The vulnerability's impact on the system and potential operational consequences should be carefully evaluated, and source-confidence limits should be considered when assessing the risk. Review context and affected scope should be validated against official advisories or CVE records to ensure accurate understanding and response. Managed environments should be checked for affected product deployments, and an owner should be assigned for follow-up actions. Monitoring, detection, and logs for exposed assets should be reviewed for extra scrutiny. Rollback/change windows and source tracking may be necessary for effective remediation and verification. Asset inventory and vulnerability management processes should be updated to reflect the potential risk and necessary mitigation strategies. Security teams should prioritize and coordinate response efforts based on the vulnerability's severity and potential impact on the organization. The vulnerability's technical details and defensive impact should be understood and communicated to relevant stakeholders to ensure effective mitigation and response. The recommended actions and additional guidance provided should be used to enhance the security posture and prevent potential exploitation of the vulnerability. The debrief and technical summary provided should be used to inform and guide response efforts, and the evidence notes and N

Recommended defensive actions

• Update Misskey to version 2026.6.0 or later
• Implement additional monitoring for concurrent access attempts
• Educate users about the importance of securing TOTP codes
• Consider implementing additional authentication factors
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-10T21:16:59.683Z and has not been modified since then. The NVD entry is currently 7.4 HIGH. Official references include commits and release notes from the Misskey project. The vulnerability was reported by a security researcher and fixed by the Misskey development team. The fix was released in version 2026.6.0. Users should verify their systems and update to the latest version.

Official resources