Unrated

Two-Factor Authentication Bypass in Kimai REST API

IdentifiersCVE-2026-52827CWE-287

CVE-2026-52827 is a two-factor authentication bypass vulnerability in Kimai affecting versions prior to 2.59.0. After successful primary credential verification, the application issues a pre-2FA session that should remain restricted until TOTP verification is completed. Due to improper authentication enforcement on REST API endpoints, this pre-2FA session is accepted by /api/* routes as fully authenticated. As a result, a user session that is still in the two-factor authentication flow can access protected API functionality without completing the second authentication factor.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

An attacker who knows a valid user's password can bypass TOTP-based two-factor authentication and obtain full authenticated REST API access with the privileges of that user. This can enable unauthorized access to application data and API actions available to the compromised account.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, restrict or disable external access to Kimai REST API endpoints, enforce additional network-layer access controls around the application, closely monitor authentication and API activity for anomalous use following password-based logins that do not complete TOTP, and require password resets for potentially exposed accounts. These measures reduce exposure but do not fully remediate the flaw.

Remediation

Patch, then assume compromise.

Upgrade Kimai to version 2.59.0 or later. The fix updates API authentication handling so that sessions still in the two-factor authentication flow are not treated as fully authenticated for REST API access, and includes regression testing to prevent recurrence.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

KimaiKimaiapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

No public activity tracked yet. Mallory keeps watching.

0 SOURCESView more in app

No public activity observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity