Kimai has an Open Redirect via Unvalidated RelayState in SAML ACS Handler

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary The SAML authentication success handler in Kimai returns the RelayState POST parameter as a redirect destination without validating the host or scheme. After a user successfully authenticates via SAML, they are redirected to an attacker-controlled URL if the IdP includes a malicious RelayState value. This enables phishing attacks that steal credentials or session tokens post-SSO. Requires SAML to be enabled (non-default configuration). Details Vulnerable file: src/Saml/Security/SamlAuthenticationSuccessHandler.php The only check is that RelayState does not equal the configured loginpath. Any external URL (e.g., https://attacker.com) passes this check and is returned as the redirect destination. The existing unit test SamlAuthenticationSuccessHandlerTest::testRelayState() confirms this behavior — an absolute URL in RelayState results in a redirect to that URL with no restriction. Steps to Reproduce Code-confirmed via unit test (testRelayState): onAuthenticationSuccess with…

Published by the source

14 Apr 2026, 01:06 UTC

Last modified by the source

14 Apr 2026, 01:06 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3jp4-mhh4-gcgr

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# Patch Next advisory brief: GHSA-3jp4-mhh4-gcgr

Advisory: Kimai has an Open Redirect via Unvalidated RelayState in SAML ACS Handler
IDs: GHSA-3jp4-mhh4-gcgr
Record: https://patchnext.com/advisories/ghsa-3jp4-mhh4-gcgr (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: kimai/kimai 2.53.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist kimai/kimai: affected <= 2.52.0; fixed in 2.53.0

## Suggested inspection (read-only)
- Packagist kimai/kimai: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on kimai/kimai.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3jp4-mhh4-gcgr (GitHub-reviewed advisory GHSA-3jp4-mhh4-gcgr lists affected ranges: Packagist kimai/kimai >=0 <=2.52.0)

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