GHSA-pfrf-9r5f-73f5 CVE-2026-29067 GO-2025-4212

ZITADEL Vulnerable to Account Takeover Due to Improper Instance Validation in V2 Login

Critical Go

Severity: 8.1 / 10; Critical · CVSS 3.1
Exploit chance (EPSS): 0.34%; Chance of exploitation in the next 30 days. Higher than 27.74% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
Fix: Available; 2 packages have a fixed version

Description

Summary

A potential vulnerability exists in ZITADEL's password reset mechanism in login V2. ZITADEL utilizes the Forwarded or X-Forwarded-Host header from incoming requests to construct the URL for the password reset confirmation link. This link, containing a secret code, is then emailed to the user.

Impact

If an attacker can manipulate these headers (e.g., via host header injection), they could cause ZITADEL to generate a password reset link pointing to a malicious domain controlled by the attacker. If the user clicks this manipulated link in the email, the secret reset code embedded in the URL can be captured by the attacker. This captured code could then be used to reset the user's password and gain unauthorized access to their account.

It's important to note that this specific attack vector is mitigated for accounts that have Multi-Factor Authentication (MFA) or Passwordless authentication enabled.

Affected Versions

Systems using the login UI (v2) and running one of the following versions are affected:

v4.x: 4.0.0-rc.1 through 4.7.0

Patches

The vulnerability has been addressed in the latest release. The patch resolves the issue by correctly validating the X-Forwarded-Host and Forwarded headers against the instance custom and trusted domains.

Before you upgrade, ensure that:

the ZITADEL_API_URL is set and is pointing to your instance, resp. system in multi-instance deployments.
the HTTP host (or a x-forwarded-host) is passed in your reverse proxy to the login UI.
a x-zitadel-instance-host (or x-zitadel-forward-host) is set in your reverse for multi-instance deployments. If you're running a single instance solution, you don't need to take any actions.

Patched versions:

4.x: Upgrade to >=4.7.1

Workarounds

The recommended solution is to update ZITADEL to a patched version.

A ZITADEL fronting proxy can be configured to delete all forwarded header values or set it to the requested host before sending requests to ZITADEL self-hosted environments.

Questions

If you have any questions or comments about this advisory, please email us at security@zitadel.com

Credits

Thanks to Amit Laish – GE Vernova for finding and reporting the vulnerability.

Affected versions

Go

Package	Vulnerable	Fixed in
github.com/zitadel/zitadel	`< 1.80.0-v2.20.0.20251208091519-4c879b47334e`	`1.80.0-v2.20.0.20251208091519-4c879b47334e`
github.com/zitadel/zitadel	`>= 1.83.4, <= 1.87.5`	No fix yet
github.com/zitadel/zitadel	`>= 4.0.0-rc.1, < 4.7.1`	`4.7.1`
github.com/zitadel/zitadel	`< 1.80.0-v2.20.0.20251208091519-4c879b47334e` `>= 1.83.4`	`1.80.0-v2.20.0.20251208091519-4c879b47334e`
github.com/zitadel/zitadel/v2	`< 1.80.0-v2.20.0.20251208091519-4c879b47334e`	`1.80.0-v2.20.0.20251208091519-4c879b47334e`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

github.com/zitadel/zitadel Go → `1.80.0-v2.20.0.20251208091519-4c879b47334e`

go

go get github.com/zitadel/zitadel@v1.80.0-v2.20.0.20251208091519-4c879b47334e && go mod tidy

github.com/zitadel/zitadel/v2 Go → `1.80.0-v2.20.0.20251208091519-4c879b47334e`

go

go get github.com/zitadel/zitadel/v2@v1.80.0-v2.20.0.20251208091519-4c879b47334e && go mod tidy

Severity breakdown

CVSS 3.1 8.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Weakness

CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

How to prevent it

Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. Use a list of approved URLs or domains to be used for redirection.
Architecture and Design: Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
Architecture and Design: Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-29067

Packages

github.com/zitadel/zitadel

Timeline

Dec 8, 2025 Published
Jun 17, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-fgmf-7rf8-m6vf ZITADEL: Actions V1 sandbox escape: host file read via require()	High	Also affects github.com/zitadel/zitadel
GHSA-9993-rfwp-rhwf ZITADEL: MFA bypass via session reuse in Login V2	High	Also affects github.com/zitadel/zitadel
GHSA-v859-c572-qh5p ZITADEL: Improper Role Revocation on Granted Projects during Multiple Role Deletions	Medium	Also affects github.com/zitadel/zitadel
GHSA-jq8w-8q2f-ffm9 ZITADEL Users Can Self-Verify Email/Phone via API	High	Also affects github.com/zitadel/zitadel
GHSA-vrh8-c9cm-wh8v ZITADEL: Unauthorized Token Privilege Escalation in OAuth2 Token Exchange	High	Also affects github.com/zitadel/zitadel
GHSA-992q-9gwp-7r79 ZITADEL: Auto-linking by email: IdP-side email verification is not checked	Medium	Also affects github.com/zitadel/zitadel
GHSA-v77h-2w3m-94hx ZITADEL: Missing Token Expiration (`exp`) Validation in JWT IdP Provider	Medium	Also affects github.com/zitadel/zitadel
GHSA-g5h5-m4hm-xjrr ZITADEL: Missing Token Audience Validation (`aud`) in JWT IdP Provider	Medium	Also affects github.com/zitadel/zitadel

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