ZeroDay Findings
Sign inSign up

Findings

CVE-2026-100347

kin-openapi is a Go project for handling OpenAPI files.

Published Oct 15, 2026 · updated Oct 15, 2026

## 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

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. 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

  2. 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

  3. Oct 15, 2026 · GitHub Advisory Database

    Fix available

    github.com/getkin/kin-openapi fixed in 0.145.0

  4. Oct 15, 2026 · GitHub Advisory Database

    Fix available

    github.com/getkin/kin-openapi fixed in 0.145.0

  5. 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

Affected

  • Go github.com/getkin/kin-openapi0 → 0.145.0
  • go github.com/getkin/kin-openapi<= 0.144.0

Sources

  • CVE.orgVulnerability recordCVE-2026-100347

    Official CVE identifier

    cve.org
  • GitHub Advisory DatabasePackage advisoryGHSA-fh4f-47mf-f2gj

    kin-openapi: Unauthenticated panic (DoS) in openapi3filter legacy router via non-canonical/unsupported HTTP method on a static path

    github.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 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

References