4.8
MEDIUM CVSS 3.1
CVE-2026-56666
ZITADEL: Auto-linking by email: IdP-side email verification is not checked
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.

INFO

Published Date :

July 10, 2026, 6:16 p.m.

Last Modified :

July 10, 2026, 6:56 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-56666 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Zitadel zitadel
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 MEDIUM MITRE-CVE
Solution
Update ZITADEL to version 4.15.3 or later to fix external identity provider linking.
  • Update ZITADEL to version 4.15.3.
  • Verify external IdP email ownership.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-56666.

URL Resource
https://github.com/zitadel/zitadel/commit/c97012f0c5dc2fe960ae6e940cbea23229f0557f
https://github.com/zitadel/zitadel/releases/tag/v4.15.3
https://github.com/zitadel/zitadel/security/advisories/GHSA-992q-9gwp-7r79
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-56666 is associated with the following CWEs:

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-56666 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-56666 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Jul. 10, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'zitadel', 'product': 'zitadel', 'versions': [{'status': 'affected', 'version': '< 4.15.3'}]}]
    Added 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.
    Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
    Added CWE CWE-287
    Added Reference https://github.com/zitadel/zitadel/commit/c97012f0c5dc2fe960ae6e940cbea23229f0557f
    Added Reference https://github.com/zitadel/zitadel/releases/tag/v4.15.3
    Added Reference https://github.com/zitadel/zitadel/security/advisories/GHSA-992q-9gwp-7r79
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.