Vulnerability · Published Oct 15, 2026 · Assigned by GitHub_M
CVE-2026-100351kin-openapi: ValidationHandler security-requirement bypass via encoded-path operation confusion
High 7.4
In plain English
A high-severity security flaw in kin-openapi from getkin. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
kin-openapi is a Go project for handling OpenAPI files. From 0.144.0 until 0.147.0, openapi3filter.ValidationHandler validates an operation selected from decoded URL.Path while a downstream gorilla/mux router configured with UseEncodedPath can dispatch a different operation selected from URL.RawPath. When a public exact route and a protected parameterized route use the same method and overlap after decoding, an unauthenticated remote request containing an encoded path separator can be validated as public and then dispatched to the protected handler without invoking the configured AuthenticationFunc. The reachable path parameter is constrained to an encoded representation that decodes to the public literal route, and proxies that canonicalize the URI before forwarding prevent this specific mismatch. This issue is fixed in version 0.147.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/getkin/kin-openapi | 0.147.0 | GHSA-23vg-4cjm-66q5 |
| Go | github.com/getkin/kin-openapi | 0.147.0 | GO-2026-6769 |
| Ubuntu:22.04:LTS | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-100351 |
| Ubuntu:24.04:LTS | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-100351 |
| Ubuntu:26.04:LTS | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-100351 |
| Ubuntu:26.10 | golang-github-getkin-kin-openapi | no fix listed | UBUNTU-CVE-2026-100351 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| getkin | kin-openapi | >= 0.144.0, < 0.147.0 |
Weakness: CWE-289, CWE-436 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N