CVE-2026-100351

kin-openapi: ValidationHandler security-requirement bypass via encoded-path operation confusion

Published Oct 15, 2026 CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-23vg-4cjm-66q5 kin-openapi: ValidationHandler security-requirement bypass via encoded-path operation confusion
History
Type Values Removed Values Added
First Time appeared Getkin
Getkin kin-openapi
Vendors & Products Getkin
Getkin kin-openapi
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title kin-openapi: ValidationHandler security-requirement bypass via encoded-path operation confusion
Weaknesses CWE-289
CWE-436
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 15, 2026, 4:09 PM
Reserved
Sep 25, 2026, 7:19 PM
Status
Deferred
Published
Oct 15, 2026, 4:17 PM
Modified
Oct 15, 2026, 5:17 PM
Severity
Important
Public date
Oct 15, 2026, 3:52 PM