kin-openapi openapi3filter: unauthenticated nil-pointer panic when validating a request against a content parameter whose media type has no schema

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-73502: 0.51% estimated exploitation activity in the next 30 days; percentile 43.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

| Field | Value | |---|---| | Ecosystem | Go | | Package | github.com/getkin/kin-openapi | | Affected versions | <= 0.143.0 (introduced in v0.2.0, PR #90, 2019-05-07; reproduced on HEAD 30e2923) | | Patched versions | 0.144.0 | --- Summary openapi3filter.ValidateRequest contains a NULL-pointer-dereference denial of service: any unauthenticated client can crash the request-validation path with a single HTTP request. When an operation declares a content parameter (as opposed to a schema parameter) whose media type object has no schema, request validation dereferences that missing schema and panics. The document is legal under the OpenAPI Specification — kin-openapi's own doc.Validate() accepts it — and the defect affects both OpenAPI 3.0.x and 3.1.x. Depending on how the library is wired into the server (see Impact), this ranges from a per-request abort with unbounded panic-log growth to a full remote process crash. Details The decoder used for content parameters when no custom…

Published by the source

18 Aug 2026, 16:38 UTC

Last modified by the source

6 Sep 2026, 03:25 UTC

Source last checked

26 Oct 2026, 15:28 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jpcw-4wr7-c3vq

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GO-2026-6112

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# Patch Next advisory brief: CVE-2026-73502

Advisory: kin-openapi openapi3filter: unauthenticated nil-pointer panic when validating a request against a `content` parameter whose media type has no schema
IDs: CVE-2026-73502, GHSA-jpcw-4wr7-c3vq
Record: https://patchnext.com/advisories/cve-2026-73502 (revision 2, source checked 26 Oct 2026, 15:28 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/getkin/kin-openapi 0.144.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/getkin/kin-openapi: affected <= 0.143.0; fixed in 0.144.0

## Suggested inspection (read-only)
- Go github.com/getkin/kin-openapi: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/getkin/kin-openapi.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GO-2026-6112 (OSV record GO-2026-6112 lists affected ranges: Go github.com/getkin/kin-openapi >=0 <0.144.0 (fixed))
- Verified: https://github.com/advisories/GHSA-jpcw-4wr7-c3vq (GitHub-reviewed advisory GHSA-jpcw-4wr7-c3vq lists affected ranges: Go github.com/getkin/kin-openapi >=0 <=0.143.0)

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