Vulnerability · Published Aug 12, 2026 · Assigned by GitHub_M
CVE-2026-73501kin-openapi: ValidationHandler.Load() Fail-Open Authentication Bypass via NoopAuthenticationFunc Default
Critical 9.1
In plain English
A critical-severity improper authentication in kin-openapi from getkin. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-github-getkin-kin-openapi | no fix listed | DEBIAN-CVE-2026-73501 |
| Debian:13 | golang-github-getkin-kin-openapi | no fix listed | DEBIAN-CVE-2026-73501 |
| Debian:14 | golang-github-getkin-kin-openapi | no fix listed | DEBIAN-CVE-2026-73501 |
| Go | github.com/getkin/kin-openapi | 0.144.0 | GO-2026-6095 |
| Go | github.com/getkin/kin-openapi | 0.144.0 | GHSA-r277-6w6q-xmqw |
| Ubuntu:22.04:LTS | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-73501 |
| Ubuntu:24.04:LTS | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-73501 |
| Ubuntu:26.04:LTS | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-73501 |
| Ubuntu:26.10 | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-73501 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| getkin | kin-openapi | < 0.144.0 |
Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N