# CVE-2026-73501 — getkin kin-openapi

> As of 2026-08-13, CVE-2026-73501 is a CRITICAL-severity vulnerability in getkin kin-openapi, CVSS v3.1 9.1. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-73501 as of 2026-08-13; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-13

## What is CVE-2026-73501?

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.

The record classifies CVE-2026-73501 under weakness class [CWE-287](https://intel.threadlinqs.com/cwe/CWE-287). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 54 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.1 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-12, last modified 2026-08-13

## Is CVE-2026-73501 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **getkin**: kin-openapi

## How to fix CVE-2026-73501

No vendor patch reference has been recorded for CVE-2026-73501 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-73501

No threat campaign in the Threadlinqs corpus currently references CVE-2026-73501, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD. Last verified by Threadlinqs on 2026-08-14. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/getkin/kin-openapi/security/advisories/GHSA-r277-6w6q-xmqw)

**Other references**

- [github.com](https://github.com/getkin/kin-openapi/commit/f0407d53b0730280266f454b755010e7eeb985da)
- [github.com (v0.144)](https://github.com/getkin/kin-openapi/releases/tag/v0.144.0)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-73501
Full detection coverage and IOCs for threats exploiting CVE-2026-73501 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp