Pocket ID is an OIDC provider that allows users to authenticate with their passkeys to services. From 2.2.0 until 2.12.0, SendEmailVerification uses the token model in backend/internal/model/email_verification_token.go to bind an email-verification token only to the user's identifier, while UpdateUser can change the account email without invalidating the outstanding token and VerifyEmail marks the current address as verified. An ordinary user can request a token for an address they control, change the account to an arbitrary unused address, and redeem the old token so Pocket ID publishes the new address with email_verified set to true. The default affected configuration uses emailsVerified=false and allowOwnAccountEdit=true; the target address must not already belong to another Pocket ID user. A relying application that trusts a verified email for automatic account matching or provisioning can link the attacker's identity to another user's account, while applications that rely exclusively on the stable OIDC sub claim are not affected by that downstream consequence. This issue is fixed in version 2.12.0.