kin-openapi is a Go project for handling OpenAPI files

Overview

kin-openapi is a Go project for handling OpenAPI files. From 0.124.0 until 0.142.0, openapi3filter.sliceMapToSlice in openapi3filter/req_resp_decoder.go converts attacker-controlled sparse indexes from a deepObject query parameter into a dense slice by allocating entries from zero through the largest supplied index, after which buildResObj creates another slice of the same length. This allocation occurs before schema validation, so maxItems does not prevent it. An unauthenticated client can send a small query such as param[items][50000000]=x to an endpoint whose deepObject schema contains an array, forcing multi-gigabyte heap allocation and causing an OOM kill or restart loop. Other request-body encodings and styled parameters that do not produce bracketed integer indexes are not affected. This issue is fixed in version 0.142.0.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Package advisory (CVE-2026-77354)

Affected packages:

• github.com/getkin/kin-openapi >= 0.124.0, < 0.142.0

Patched in:

• github.com/getkin/kin-openapi 0.142.0

Source: https://github.com/advisories/GHSA-xhj3-7xw9-vr34

Vendor advisories

• Red Hat VEX · Important · affected: Migration Toolkit for Applications 8, Multicluster Global Hub, OpenShift Serverless, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat Ceph Storage 6, Red Hat Ceph Storage 7, … · no fix planned: Red Hat Ceph Storage 6, Red Hat Ceph Storage 7, Red Hat Ceph Storage 8, Red Hat Ceph Storage 9, … · updated 2026-09-14 · vex