Is CVE-2026-100347 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100347 being exploited in the wild.

How severe is CVE-2026-100347?

Medium severity, with a CVSS score of 5.3, published 15 October 2026.

Which products and versions are affected?

github.com/getkin/kin-openapi (Go) <= 0.144.0, SEMVER:introduced=0,fixed=0.145.0; Kin-Openapi 0.144.0 and earlier.

Is there a fix for CVE-2026-100347?

Yes. github.com/getkin/kin-openapi (Go): upgrade to 0.145.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-100347 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-100347?

Check whether you run github.com/getkin/kin-openapi (Go) or Kin-Openapi at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100347: kin-openapi: Unauthenticated denial of service in legacy router

Q: Is there a fix for CVE-2026-100347?

Yes. github.com/getkin/kin-openapi (Go): upgrade to 0.145.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-100347 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-100347?

Check whether you run github.com/getkin/kin-openapi (Go) or Kin-Openapi at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100347 · Severity: medium · CVSS 5.3 · Published 2026-10-15

kin-openapi is a Go library that validates HTTP requests against OpenAPI specifications. An unauthenticated attacker can crash individual connection handlers by sending requests with non-standard or lowercase HTTP methods to any static path in the spec, causing the process to log unbounded error messages and reset connections before authentication is checked.

Technologies: github.com/getkin/kin-openapi (Go). Vendors: Go.

Quick answers

Is CVE-2026-100347 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100347 being exploited in the wild.
How severe is CVE-2026-100347?: Medium severity, with a CVSS score of 5.3, published 15 October 2026.
Which products and versions are affected?: github.com/getkin/kin-openapi (Go) <= 0.144.0, SEMVER:introduced=0,fixed=0.145.0; Kin-Openapi 0.144.0 and earlier.
Is there a fix for CVE-2026-100347?: Yes. github.com/getkin/kin-openapi (Go): upgrade to 0.145.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-100347 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-100347?: Check whether you run github.com/getkin/kin-openapi (Go) or Kin-Openapi at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/getkin/kin-openapi (Go): upgrade to 0.145.0 or later
```
go get github.com/getkin/kin-openapi@v0.145.0
```

Technical details

The legacy router in openapi3filter matches request methods verbatim against a trie built only with uppercase canonical HTTP methods. Non-canonical methods (e.g., lowercase "get") or unsupported-but-valid tokens (e.g., "PROPFIND") miss the trie, and when targeting an existing static path, the code calls `PathItem.GetOperation()` with the unrecognized method, triggering a panic before authentication. Go's net/http recovers the per-connection panic, aborts the connection, and logs a stack trace; repeated requests cause log growth and availability degradation.

Affected products

kin-openapi kin-openapi 0.144.0 and earlier

Identifiers

CVE-2026-100347
GHSA-fh4f-47mf-f2gj
GO-2026-6783

Timeline

2026-10-15: disclosed

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