Summary
Kimai: Pre-2FA KIMAI_SESSION cookie grants full authenticated REST API access, bypassing TOTP
Two-factor authentication (TOTP) can be fully bypassed for the REST API. The KIMAI_SESSION cookie returned in the response to the login request; issued after only the password is verified, before the TOTP step; is already accepted as authenticated by every /api/* endpoint.
So after submitting just the password, the web UI correctly holds the browser at the TOTP screen (/en/auth/2fa), but the cookie from that same login response can be replayed against the API to act as the user without ever entering the second factor. This affects any account with 2FA enabled and requires only the account password.
Details
Affected Component
- The API firewall / authorization.
config/packages/security.yaml guards the API with { path: '^/api', roles: IS_AUTHENTICATED }. During 2FA the session carries a Scheb TwoFactorToken, which satisfies IS_AUTHENTICATED (it is a real, non-anonymous token). App\API\Authentication\ApiRequestMatcher returns !$request->hasPreviousSession(), so a request that carries the login session skips the stateless API firewall and is served by the main session firewall; Scheb's TwoFactorAccessDecider::isAccessible() then evaluates IS_AUTHENTICATED to true for ^/api and lets it through, and App\Voter\ApiVoter grants API to any token whose user is a User. Web routes are not affected because they require concrete roles (e.g. ROLE_USER) that a TwoFactorToken does not hold.
PoC
A PoC was provided, but removed for security reasons.
Impact
Two-factor authentication provides no protection for the REST API. If an attacker obtains a user's password (phishing, credential stuffing, reuse, breach); exactly the threat 2FA is meant to defend against; they get full authenticated API access as that user without the second factor. The whole exploit is a single cookie taken from the login response; no API token, Bearer header or CSRF token is required.
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
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.
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- The
/api/firewall now usesIS_AUTHENTICATED_REMEMBEREDwhich is only assigned after 2FA. The historically usedIS_AUTHENTICATEDflag is applied immediately after login and before 2FA happened. - The APIVoter checks both
$token instanceof TwoFactorTokenInterfaceandisGranted('IS_AUTHENTICATED_2FA_IN_PROGRESS', $user)to make sure that the user is not currently in the 2FA step. - Regression tests were added to prevent future escalation of the same issue.
See https://www.kimai.org/en/security/ghsa-v8hx-4vx8-wc96 for more information.
Frequently Asked Questions
- What is CVE-2026-52827? CVE-2026-52827 is a high-severity improper authentication vulnerability in kimai/kimai (composer), affecting versions < 2.59.0. It is fixed in 2.59.0. The application does not adequately verify the identity of a user, device, or process before granting access.
- Which versions of kimai/kimai are affected by CVE-2026-52827? kimai/kimai (composer) versions < 2.59.0 is affected.
- Is there a fix for CVE-2026-52827? Yes. CVE-2026-52827 is fixed in 2.59.0. Upgrade to this version or later.
- Is CVE-2026-52827 exploitable, and should I be worried? Whether CVE-2026-52827 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-2026-52827 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-2026-52827? Upgrade
kimai/kimaito 2.59.0 or later.