vulnerability / NVI-00015083 / Revision 1
kin-openapi: ValidationHandler.Load() Fail-Open Authentication Bypass via NoopAuthenticationFunc Default
GitHub lists this reviewed advisory for github.com/getkin/kin-openapi. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
9.1 critical
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/getkin/kin-openapi
source listed<= 0.143.0
### Summary `ValidationHandler.Load()` in `getkin/kin-openapi` silently replaces a nil `AuthenticationFunc` with `NoopAuthenticationFunc`, which always returns `nil` without performing any credential check. Because this substitution happens unconditionally when the caller omits the field, every OpenAPI `security` requirement declared in the spec is silently satisfied for unauthenticated requests. An unauthenticated remote attacker can reach handlers for routes whose OpenAPI operation requires an API key, OAuth token, or any other security scheme if the application relies on `ValidationHandler` as its enforcement middleware. ### Details `ValidationHandler` is an HTTP middleware exported by `openapi3filter` that validates incoming requests and responses against a loaded OpenAPI specification. Its `Load()` method initialises default fields before the handler begins serving: ```go // openapi3filter/validation_handler.go:47-49 if h.AuthenticationFunc == nil { h.AuthenticationFunc = NoopAuthenticationFunc } ``` `NoopAuthenticationFunc` is defined as: ```go // openapi3filter/validation_handler.go:17-18 func NoopAuthenticationFunc(context.Context, *AuthenticationInput) error { ret
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-r277-6w6q-xmqw ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.