getkin kin-openapi up to 0.143.x ValidationHandler validation_handler.go ValidationHandler.Load improper authentication

Summaryinfo

A vulnerability was found in getkin kin-openapi up to 0.143.x. It has been classified as critical. This affects the function ValidationHandler.Load of the file openapi3filter/validation_handler.go of the component ValidationHandler. The manipulation leads to improper authentication. This vulnerability is listed as CVE-2026-73501. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in getkin kin-openapi up to 0.143.x. It has been rated as critical. This issue affects the function ValidationHandler.Load of the file openapi3filter/validation_handler.go of the component ValidationHandler. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

kin-openapi is a Go project for handling OpenAPI files. Prior to 0.144.0, ValidationHandler.Load() in openapi3filter/validation_handler.go silently replaces a nil AuthenticationFunc with NoopAuthenticationFunc, which returns nil without checking credentials. This substitution causes every OpenAPI security requirement to be satisfied for unauthenticated requests when an application relies on ValidationHandler as its enforcement middleware. The no-op callback prevents the fail-closed ErrAuthenticationServiceMissing path from being reached and forwards the request to protected handlers that may require an API key, OAuth token, or another security scheme. This issue is fixed in version 0.144.0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-73501 since 08/12/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 0.144.0 eliminates this vulnerability.

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Productinfo

Vendor

• getkin

Name

• kin-openapi

Version

• 0.143

Website

• Product: https://github.com/getkin/kin-openapi/

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