How severe is GHSA-3jp4-mhh4-gcgr?

GHSA-3jp4-mhh4-gcgr has a CVSS score of 0/10, rated NONE. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-3jp4-mhh4-gcgr?

GHSA-3jp4-mhh4-gcgr affects the following packages: kimai/kimai (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-3jp4-mhh4-gcgr?

Update kimai/kimai to 2.53.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3jp4-mhh4-gcgr is resolved across your whole dependency graph.

How do I detect GHSA-3jp4-mhh4-gcgr in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kimai/kimai. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-3jp4-mhh4-gcgr if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-3jp4-mhh4-gcgr?

O3 pinpoints whether GHSA-3jp4-mhh4-gcgr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-3jp4-mhh4-gcgr actively exploited in the wild?

No public exploit code has been indexed for GHSA-3jp4-mhh4-gcgr yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-3jp4-mhh4-gcgr published, and has it been updated?

GHSA-3jp4-mhh4-gcgr was published on April 14, 2026 and was last updated on April 14, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

GHSA-3jp4-mhh4-gcgr

NONE

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

Published

Apr 14, 2026

Updated

Apr 14, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🐘kimai/kimai

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

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

// Line 27-33
$relayState = $request->request->get('RelayState', $request->query->get('RelayState'));
if (\is_scalar($relayState)) {
    $relayState = (string) $relayState;
    if ($relayState !== $this->httpUtils->generateUri($request, (string) $this->options['login_path'])) {
        return $relayState;  // No host/scheme validation — any URL accepted
    }
}

The only check is that RelayState does not equal the configured login_path. 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

1. Enable SAML authentication in Kimai
2. Configure a SAML IdP (e.g., SimpleSAMLphp)
3. Initiate IdP-initiated SSO with RelayState=https://attacker.com
   — or intercept the ACS POST and modify RelayState to https://attacker.com
4. Complete SAML authentication at the IdP
5. Observe: after the SAMLResponse POST to /saml/acs, Kimai issues:
   HTTP/1.1 302 Found
   Location: https://attacker.com

Code-confirmed via unit test (testRelayState): onAuthenticationSuccess with RelayState=http://localhost/relayed redirects directly to that URL. External URLs follow the same code path.

Impact

While this bug exists it has low practical possibilities and the attacker needs to be able to create a SAML request, meaning either admin access to an IdP supporting such an action OR access to the private SAML keys / certificates.

In other words: only exploitable in IdP-initiated SSO flows where the IdP includes a RelayState value supplied by the attacker (e.g., via a malicious link to the IdP).

Fix

The RelayState is validated before redirecting, see #5878

It may not contain a host or port and cannot start with //.
If it contains a host, it must match the current host.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`kimai/kimai`	all versions	2.53.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kimai/kimai. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update kimai/kimai to 2.53.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3jp4-mhh4-gcgr is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-3jp4-mhh4-gcgr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-3jp4-mhh4-gcgr. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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` ```php // Line 27-33 $relayState = $request->reques

O3 Security · Impact-Aware SCA

Is GHSA-3jp4-mhh4-gcgr in your dependencies?

O3 detects GHSA-3jp4-mhh4-gcgr across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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