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.
Exploitability
AV:NAC:HAT:PPR:NUI:AVulnerable System
VC:HVI:HVA:NSubsequent System
SC:NSI:NSA:N7.4/CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NOther