Is CVE-2026-121553 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-121553?

CVE-2026-121553 has a CVSS v3 severity of MEDIUM (4.8).

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CVE-2026-121553

Description

Cotonti through 1.0.0 generates registration and email-change validation tokens with md5(microtime()), allowing attackers to bypass email-ownership verification by predicting tokens. Attackers can derive the generation time from the HTTP Date header and compute candidate tokens offline. They then submit these tokens to the users.register.php validate handler to activate accounts or confirm email addresses they do not control.