CVE-2026-73502 kin-openapi openapi3filter: unauthenticated nil-pointer panic when validating a request against a `content` parameter whose media type has no schema
An unauthenticated attacker can cause a denial of service by sending a request that triggers a nil-pointer panic in the kin-openapi library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73502?
CVE-2026-73502 is a medium-severity vulnerability in getkin kin-openapi, published on 18 Aug 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. 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.
Weakness: CWE-476
Which versions are affected by CVE-2026-73502?
3 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 | 0.144.0 |
github.com/getkin/kin-openapi Go | All versions | 0.144.0 |
github.com/getkin/kin-openapi Go | All versions | 0.144.0 |
How do I fix CVE-2026-73502?
Upgrade github.com/getkin/kin-openapi to 0.144.0 or later.
Is CVE-2026-73502 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73502 exists.
Sources
Also known as CLEANSTART-2026-FV65600, CLEANSTART-2026-IY00574, CLEANSTART-2026-ND84932, CLEANSTART-2026-RJ16985, DEBIAN-CVE-2026-73502, GHSA-jpcw-4wr7-c3vq and 45 more.