kin-openapi: Nil-pointer dereference panic in openapi3filter for OpenAPI 3.1 array schemas missing items

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

kin-openapi is a Go project for handling OpenAPI files. From 0.136.0 until 0.143.0, openapi3filter accepts OpenAPI 3.1 array schemas without an items keyword and then dereferences the nil Schema.Items value while decoding application/x-www-form-urlencoded or multipart/form-data request bodies, response headers, and other array parameter surfaces. A remote unauthenticated client can reach an affected operation with a nonempty request or matching response and deterministically trigger a nil-pointer panic during ValidateRequest or ValidateResponse. OpenAPI 3.0 documents are not affected because document validation rejects arrays without items, and JSON request bodies use a different decoder path. This issue is fixed in version 0.143.0.

[ Fixes ]Fixes and patches

• github.com/getkin/kin-openapi 0.143.0Fixed version · GitHub Advisories · go package github.com/getkin/kin-openapi: upgrade to 0.143.0 or later (affected >= 0.136.0, < 0.143.0)

[ Packages ]Affected open-source packages

• github.com/getkin/kin-openapi goAffected >= 0.136.0, < 0.143.0 · fixed in 0.143.0 · GHSA-p6wj-qrr4-pgh5

[ References ]References

• github.com/getkin/kin-openapi/commit/30e292371a89ca6d1f91a9553e0aa518b49f838d
• github.com/getkin/kin-openapi/releases/tag/v0.143.0
• github.com/getkin/kin-openapi/security/advisories/GHSA-p6wj-qrr4-pgh5
• github.com/opnsense/core/security/advisories/GHSA-26cj-h9rj-g5pf