CVE-2026-65840 (CVSS 9.6)

Fider is a feedback portal for feature requests and suggestions. Prior to version 0.36.0, in multi-tenant mode (HOST_MODE=multi), an attacker can use an email verification key issued by Tenant A to authenticate as the same email address on Tenant B. This completely bypasses tenant isolation and allows unauthorized account takeover across tenants. Single-host deployments (HOST_MODE=single, the default) are NOT affected. This issue has been patched in version 0.36.0.