Summary
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.
Affected Versions
Systems running one of the following versions are affected:
- 4.x:
4.0.0through4.11.0(including RC version) - 3.x:
3.0.0to3.4.6(including RC versions) - 2.x:
2.59.0to2.71.19
Workarounds
The recommended solution is to update Zitadel to a patched version.
If an upgrade is not possible, users can prevent actions from using unintended endpoints by setting network policies or firewall rules in your infrastructure. Note that this is outside of the functionality provided by ZITADEL.
Questions
If there are any questions or comments about this advisory, please send an email to [email protected]
Credits
This vulnerability was found by zentrust partners GmbH during a scheduled penetration test. Thank you to the analysts Martin Tschirsich, Joud Zakharia, Christopher Baumann.
The full report will be made public after the complete review.
Impact
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.
Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
The vulnerability has been addressed in the latest releases. The patch 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.
4.x: Upgrade to >=4.11.1
3.x: Update to >=v4.11.1 or check out workarounds
2.x: Update to >=v4.11.1 or check out workarounds
Frequently Asked Questions
- What is CVE-2026-27945? CVE-2026-27945 is a low-severity server-side request forgery (SSRF) vulnerability in github.com/zitadel/zitadel/v2 (go), affecting versions >= 2.59.0, < 4.11.1. It is fixed in 4.11.1, 1.80.0-v2.20.0.20260225053328-b2532e966621. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
- Which versions of github.com/zitadel/zitadel/v2 are affected by CVE-2026-27945? github.com/zitadel/zitadel/v2 (go) versions >= 2.59.0, < 4.11.1 is affected.
- Is there a fix for CVE-2026-27945? Yes. CVE-2026-27945 is fixed in 4.11.1, 1.80.0-v2.20.0.20260225053328-b2532e966621. Upgrade to this version or later.
- Is CVE-2026-27945 exploitable, and should I be worried? Whether CVE-2026-27945 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-27945 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-27945?
- Upgrade
github.com/zitadel/zitadel/v2to 4.11.1 or later - Upgrade
github.com/zitadel/zitadel/v2to 1.80.0-v2.20.0.20260225053328-b2532e966621 or later
- Upgrade