Zitadel up to 4.11.0 API server-side request forgery

Summaryinfo

A vulnerability, which was classified as critical, has been found in Zitadel up to 4.11.0. Impacted is an unknown function of the component API. The manipulation leads to server-side request forgery. This vulnerability is uniquely identified as CVE-2026-27945. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Zitadel up to 4.11.0. It has been rated as critical. This issue affects an unknown functionality of the component API. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

ZITADEL is an open source identity management platform. Zitadel Action V2 (introduced as early preview in 2.59.0, beta in 3.0.0 and GA in 4.0.0) is a webhook based approach to allow developers act on API request to Zitadel and customize flows such the issue of a token. Zitadel's Action target URLs can point to local hosts, potentially allowing adversaries to gather internal network information and connect to internal services. When the URL points to a local host / IP address, an adversary might gather information about the internal network structure, the services exposed on internal hosts etc. This is sometimes called a Server-Side Request Forgery (SSRF). Zitadel Actions expect responses according to specific schemas, which reduces the threat vector. The patch in version 4.11.1 resolves the issue by checking the target URL against a denylist. By default localhost, resp. loopback IPs are denied. Note that this fix was only released on v4.x. Due to the stage (preview / beta) in which the functionality was in v2.x and v3.x, the changes that have been applied to it since then and the severity, respectively the actual thread vector, a backport to the corresponding versions was not feasible. Please check the workaround section for alternative solutions if an upgrade to v4.x is not possible. If an upgrade is not possible, prevent actions from using unintended endpoints by setting network policies or firewall rules in one's own infrastructure. Note that this is outside of the functionality provided by Zitadel.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-27945 since 02/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are required for exploitation. Neither technical details nor an exploit are publicly available.

Upgrading to version 4.11.1 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-8793). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Zitadel

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11.0

Website

• Product: https://github.com/zitadel/zitadel/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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