CVE-2025-57770: zitadel Observable Discrepancy

Vulnerability summary

CVE-2025-57770 is a medium (CVSS 5.3) Observable Discrepancy vulnerability in zitadel. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30% of scored vulnerabilities.

Timeline

1. 22-08-2025
   PublishedVulnerability first disclosed.
2. 22-08-2025
   Last modifiedVulnerability information updated.

Description

The open-source identity infrastructure software Zitadel allows administrators to disable the user self-registration. Versions 4.0.0 to 4.0.2, 3.0.0 to 3.3.6, and all versions prior to 2.71.15 are vulnerable to a username enumeration issue in the login interface. The login UI includes a security feature, Ignoring unknown usernames, that is intended to prevent username enumeration by returning a generic response for both valid and invalid usernames. This vulnerability allows an unauthenticated attacker to bypass this protection by submitting arbitrary userIDs to the select account page and distinguishing between valid and invalid accounts based on the system's response. For effective exploitation, an attacker needs to iterate through possible userIDs, but the impact can be limited by implementing rate limiting or similar measures. The issue has been patched in versions 4.0.3, 3.4.0, and 2.71.15.

• CWE-203Observable DiscrepancyThe product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.