CVE-2026-73502
Received Received - Intake

NULL Pointer Dereference in kin-openapi OpenAPI Validation

Publication date: 2026-08-18

Last updated on: 2026-08-18

Assigner: GitHub, Inc.

Description
kin-openapi is a Go project for handling OpenAPI files. From 0.2.0 until 0.144.0, openapi3filter.ValidateRequest can encounter a NULL-pointer-dereference denial of service when an operation declares a content parameter whose application/json media type has no schema. In openapi3filter/req_resp_decoder.go, the default defaultContentParameterDecoder dereferences mt.Schema.Value without checking whether mt.Schema is nil, even though doc.Validate() accepts the document under OpenAPI 3.0.x and 3.1.x. A single unauthenticated request supplying the parameter value can panic request validation, causing an aborted request with log growth in the common synchronous net/http path or a full process crash in integrations without recovery. This issue is fixed in version 0.144.0.

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Meta Information

Published
2026-08-18
Last Modified
2026-08-18
Generated
2026-08-18
AI Q&A
2026-08-18
EPSS Evaluated
N/A
NVD
CVE-2026-73502
EUVD
EUVD-2026-61142

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
kin-openapi openapi3filter to 0.144.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.

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Executive Summary

This vulnerability is a NULL-pointer dereference in the kin-openapi Go library affecting versions up to 0.143.0. It occurs when validating a request with a content parameter whose media type has no schema. The defaultContentParameterDecoder function crashes by dereferencing a nil schema, causing a panic during request validation.

Detection Guidance

Check if your kin-openapi library version is below 0.144.0 using commands like 'go list -m github.com/getkin/kin-openapi' in Go projects. Monitor application logs for nil-pointer panic errors during request validation.

Impact Analysis

This vulnerability can cause denial-of-service conditions. It may abort request validation with log growth or crash the entire process if the library is integrated without recovery mechanisms. An unauthenticated attacker can exploit it if the target operation lacks security requirements.

Mitigation Strategies

Upgrade kin-openapi to version 0.144.0 or later. If immediate upgrade is not possible, ensure content parameters declare schemas or implement custom ParamDecoders with nil checks to prevent dereferencing.

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