# CVE-2026-100348: kin-openapi OpenAPI spec loader nil-pointer panic on self-referential additionalProperties

Source: https://junglewise.ai/threats/cve-2026-100348-kin-openapi-spec-loader-panics-on-a-self-referential  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-15. Updated: 2026-10-15  
License: CC BY 4.0 with a link back

CVE-2026-100348 · Severity: medium · CVSS 5.3 · Published 2026-10-15

kin-openapi is a Go library for parsing and validating OpenAPI specifications. A maliciously crafted OpenAPI document can crash the loader during spec parsing, causing a denial of service in any tool or service that ingests untrusted specs—such as API registries, management platforms, linters, or converters.

Technologies: [github.com/getkin/kin-openapi (Go)](https://junglewise.ai/threats/technologies/github-com-getkin-kin-openapi). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-100348 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100348 being exploited in the wild.

**How severe is CVE-2026-100348?** Medium severity, with a CVSS score of 5.3, published 15 October 2026.

**Which products and versions are affected?** github.com/getkin/kin-openapi (Go) <= 0.144.0, SEMVER:introduced=0,fixed=0.145.0; Kin-Openapi up to v0.144.0.

**Is there a fix for CVE-2026-100348?** Yes. github.com/getkin/kin-openapi (Go): upgrade to 0.145.0 or later. Until then: Restrict the loading of untrusted OpenAPI specifications, or run the loader in a sandboxed environment with crash recovery. Alternatively, validate specs through an intermediate safe parser before passing to kin-openapi's loader.</anigation>
<parameter name="timeline">[{"kind": "disclosed", "at": "2026-10-15"}] Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-100348 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-100348?** Check whether you run github.com/getkin/kin-openapi (Go) or Kin-Openapi at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/getkin/kin-openapi (Go): upgrade to 0.145.0 or later

  ```sh
  go get github.com/getkin/kin-openapi@v0.145.0
  ```


Restrict the loading of untrusted OpenAPI specifications, or run the loader in a sandboxed environment with crash recovery. Alternatively, validate specs through an intermediate safe parser before passing to kin-openapi's loader.</anigation>
<parameter name="timeline">[{"kind": "disclosed", "at": "2026-10-15"}]

## Technical details

The vulnerability is a nil-pointer dereference in the loader's resolveComponent function (openapi3/loader.go line 455) when processing a schema with a self-referential $ref that targets the schema's own additionalProperties field. The code dereferences c.Value.AdditionalProperties without checking whether c.Value is nil, which occurs when a $ref fragment drills through additionalProperties of a not-yet-resolved schema. This triggers a panic during LoadFromData/LoadFromFile/LoadFromURI before validation occurs, with no recovery handler in the loader.

## Affected products

- kin-openapi kin-openapi up to v0.144.0

## Identifiers

- CVE-2026-100348
- GHSA-mh7x-f8wq-4jhx
- GO-2026-6789

## Related threats

- [kin-openapi uncontrolled recursion on circular allOf/anyOf/oneOf schemas](https://junglewise.ai/threats/cve-2026-100354-kin-openapi-uncontrolled-recursion-on-circular-allof-anyof-oneof)
- [kin-openapi SecurityHandler authentication bypass via path encoding](https://junglewise.ai/threats/cve-2026-100351-kin-openapi-validationhandler-security-requirement-bypass-via)
- [kin-openapi deepObject query decoding DoS via repeated regexp compilation](https://junglewise.ai/threats/cve-2026-100350-kin-openapi-deepobject-query-decoding-repeatedly-compiles-an)
- [kin-openapi: Unauthenticated denial of service in legacy router](https://junglewise.ai/threats/cve-2026-100347-kin-openapi-unauthenticated-panic-dos-in-openapi3filter-legacy)
- [kin-openapi nil pointer dereference in query/body array decoding](https://junglewise.ai/threats/cve-2026-100353-kin-openapi-incomplete-fix-for-ghsa-p6wj-qrr4-pgh5-three)