CVE-2026-100349 kin-openapi openapi3filter: nil-pointer panic in ValidateResponse on a response header declared with content

High 8.2 Published 15 Oct 2026 Updated 16 Oct 2026

A nil-pointer dereference in kin-openapi causes a panic during response validation, leading to denial of service for applications processing untrusted OpenAPI specifications.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-100349?

CVE-2026-100349 is a high-severity vulnerability in getkin kin-openapi, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

kin-openapi is a Go project for handling OpenAPI files. Prior to 0.146.0, openapi3filter.ValidateResponse passes a nil response header schema to decodeValue when an OpenAPI document declares the header with content instead of schema. The document passes validation, but every response validation for the affected operation dereferences the nil schema and panics even when the response does not contain the declared header. Applications that ingest an untrusted specification can expose this as remote availability impact, while applications using only trusted local specifications still crash when the affected operation is exercised. This issue is fixed in version 0.146.0.

Weakness: CWE-476

Which versions are affected by CVE-2026-100349?

2 open source packages ship an affected version, including github.com/getkin/kin-openapi.

Package	Affected	Fixed in
`github.com/getkin/kin-openapi` Go	All versions	`0.146.0`
`github.com/getkin/kin-openapi` Go	All versions	`0.146.0`

How do I fix CVE-2026-100349?

Upgrade github.com/getkin/kin-openapi to 0.146.0 or later.

Is CVE-2026-100349 being exploited?

There is no known exploitation of CVE-2026-100349 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2026-100349, ECHO-94bc-babb-e070, GHSA-74vm-87hj-r66f, MINI-2c59-c62r-f5m2, MINI-3pcc-373v-xf5g, MINI-4q9c-fqc2-69cc and 30 more.