OpenMetadata EUVD-2026-66605

The victim must follow an attacker-crafted OpenMetadata login URL that contains a manipulated callback (SAML flow) or equivalent redirect parameter (OIDC/OAuth2 flow) pointing to an attacker-controlled destination. The victim must then successfully complete the authentication ceremony against the configured identity provider. No prior OpenMetadata account or credentials are required by the attacker - only the ability to deliver the crafted URL to a target who has a valid identity provider account. Exploitation is limited to deployments with SAML, OIDC, or OAuth2 authentication enabled; deployments using only local username/password authentication without an external identity provider are not affected by this code path. Exploitation is further constrained by the active user interaction requirement: the victim must click the link and authenticate, making automated or opportunistic mass exploitation impractical without a phishing infrastructure.

The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N) scores 8.5, correctly reflecting network reachability, low complexity, no privilege requirement, mandatory active user interaction, and high confidentiality plus integrity impact. Real-world risk is high for any internet-facing OpenMetadata deployment using SAML or OIDC, because the exploit requires only a crafted URL and a phishing step - no memory corruption, no complex chaining. The primary risk-reducing factor is the required user interaction (UI:A): the victim must click the crafted link and complete authentication, which requires social engineering. KEV status is not confirmed from the provided data, and no public exploit code has been identified at time of analysis, which somewhat limits opportunistic exploitation. However, the attack primitive is trivially constructable by anyone who reads the VulnCheck advisory and the referenced GitHub issue. The broad CPE coverage (all versions with no upper 1.x bound) and the absence of any 1.x patch means a large portion of deployed instances remain vulnerable. Deployments reachable only from internal networks face meaningfully reduced risk given the social engineering requirement.

An attacker registers a server at attacker.example.com and crafts an OpenMetadata login URL with the callback parameter set to https://attacker.example.com/capture, then delivers this link to a targeted employee via a phishing email. The employee clicks the link, is prompted to authenticate via their corporate SAML IdP, and upon successful login OpenMetadata's assertion consumer servlet redirects their browser to https://attacker.example.com/capture?token=<JWT>&email=victim@corp.com&name=Jane+Doe. The attacker's server logs the request, extracts the JWT, and immediately uses it in Authorization headers to call OpenMetadata's API as the victim, reading sensitive metadata catalogues, modifying lineage, or escalating further.