CVE-2026-100347
kin-openapi is a Go project for handling OpenAPI files.
Published Oct 15, 2026 · corrected/updated Oct 16, 2026 · evidence confidence high
## Summary The (the exported, documented request-validation middleware) hard-wires the legacy router ( ). That router matches the incoming request method verbatim against a trie built exclusively from upper-cased canonical HTTP methods. A request carrying a method token that is not one of the 9 standard methods — a legitimate-but-unsupported token such as , or a non-canonical case variant such as lowercase — misses the trie, leaves , and for an existing **static** path falls through to , whose case calls . The panic fires inside route resolution, **before any authentication** runs. This is an unauthenticated, remotely triggerable denial of service (recovered per-connection panic + unbounded error-log growth). ## Root Cause - — always constructs ; there is no alternative router option on this path. - — the request method is used verbatim ( ); there is no canonicalization or rejection of unknown method tokens. - — the trie is populated with keys taken from (canonical constants only). - — misses for a non-canonical/unsupported method → . - — in the block, returns non-nil for an existing static path, and control reaches . - — 's has no matching case → . ## Impact An unauthenticated attacker sends a single request with a non-standard HTTP method token to any existing static path. The handler goroutine panics; Go's recovers the panic per connection (process survives), aborts the connection (client sees a reset / 500), and logs a full stack trace. Repeated requests cause connection churn and unbounded log growth, and the request never reaches authentication. Availability impact (A:L) under the default synchronous middleware; on non-net/http hosts or when reached on an application goroutine the ceiling is a full crash. ## Proof of Concept Serve any spec with a static path (e.g. ) behind , then: Reproduced end-to-end against a real + : and lowercase both abort the connection with a panic at (stack: <- router.go:150 <- validation_handler.go:84); the process stays alive and su
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-100347 is a medium public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: golang-github-getkin-kin-openapi (0.110.0-1, 0.117.0-1, 0.118.0-1); golang-github-getkin-kin-openapi (0.124.0-1, 0.135.0-1); golang-github-getkin-kin-openapi (0.124.0-1, 0.135.0-1); github.com/getkin/kin-openapi (0 → 0.145.0). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 5.3, EPSS 0.5%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-20, CWE-248. Sources contributing to this record: cve_org, epss, github, gitlab. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 15, 2026 · NIST NVD
Detected
kin-openapi is a Go project for handling OpenAPI files. Prior to 0.145.0, openapi3filter.ValidationHandler uses the routers/legacy router, which passes an unsupported or non-canonical HTTP method for an existing static path to openapi3.PathItem.GetOperation. The default branch of GetOperation panics before authentication runs, so an unauthenticated remote client can repeatedly send methods such as
Oct 15, 2026 · NIST NVD
Updated
kin-openapi is a Go project for handling OpenAPI files. Prior to 0.145.0, openapi3filter.ValidationHandler uses the routers/legacy router, which passes an unsupported or non-canonical HTTP method for an existing static path to openapi3.PathItem.GetOperation. The default branch of GetOperation panics before authentication runs, so an unauthenticated remote client can repeatedly send methods such as
Oct 15, 2026 · GitHub Advisory Database
Fix available
github.com/getkin/kin-openapi fixed in 0.145.0
Oct 15, 2026 · GitHub Advisory Database
Fix available
github.com/getkin/kin-openapi fixed in 0.145.0
Oct 15, 2026 · GitHub Advisory Database
Updated
## Summary The (the exported, documented request-validation middleware) hard-wires the legacy router ( ). That router matches the incoming request method verbatim against a trie built exclusively from upper-cased canonical HTTP methods. A request carrying a method token that is not one of the 9 standard methods — a legitimate-but-unsupported token such as , or a non-canonical case variant such as
Oct 16, 2026 · OSV.dev
Updated
kin-openapi is a Go project for handling OpenAPI files. Prior to 0.145.0, openapi3filter.ValidationHandler uses the routers/legacy router, which passes an unsupported or non-canonical HTTP method for an existing static path to openapi3.PathItem.GetOperation. The default branch of GetOperation panics before authentication runs, so an unauthenticated remote client can repeatedly send methods such as
Affected
- Debian:12 golang-github-getkin-kin-openapi0.110.0-1, 0.117.0-1, 0.118.0-1
- Debian:13 golang-github-getkin-kin-openapi0.124.0-1, 0.135.0-1
- Debian:14 golang-github-getkin-kin-openapi0.124.0-1, 0.135.0-1
- Go github.com/getkin/kin-openapi0 → 0.145.0
- go github.com/getkin/kin-openapi<= 0.144.0
- golang github.comversion unspecified
Sources
- CVE.orgVulnerability recordCVE-2026-100347
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-100347
30-day exploitation probability 0.5%
first.org - GitHub Advisory DatabasePackage advisoryGHSA-fh4f-47mf-f2gj
GitHub Advisory Database record mirrored by OSV.
github.com - GitLab Advisory DatabasePackage advisoryCVE-2026-100347
The openapi3filter.ValidationHandler (the exported, documented request-validation middleware) hard-wires the legacy router (routers/legacy). That router matches the incoming request method verbatim against a trie built exclusively from upper-cased canonical HTTP methods. A request carrying a method token that is not one of the 9 standard methods — a legitimate-but-unsupported token such as PROPFIN
advisories.gitlab.com - NIST NVDVulnerability recordCVE-2026-100347
kin-openapi is a Go project for handling OpenAPI files. Prior to 0.145.0, openapi3filter.ValidationHandler uses the routers/legacy router, which passes an unsupported or non-canonical HTTP method for an existing static path to openapi3.PathItem.GetOperation. The default branch of
nvd.nist.gov - OSV.devPackage advisoryDEBIAN-CVE-2026-100347osv.dev
- OSV.devPackage advisoryGHSA-fh4f-47mf-f2gj
kin-openapi: Unauthenticated panic (DoS) in openapi3filter legacy router via non-canonical/unsupported HTTP method on a static path
osv.dev