CVE-2026-57574
Misskey is an open source, federated social media platform. Prior to 2026.6.0, Misskey contains a vulnerability in Time-based One-Time Password (TOTP) authentication in UserAuthService where insufficient validation of used tokens allows the reuse of a single-use code within its valid time step. If both credentials and a TOTP code are obtained concurrently, an attacker may reuse the code to perform unauthorized actions, potentially leading to account takeover. This issue is fixed in version 2026.6.0.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 4.0 : 7.4 HIGH
Vector: AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.