What’s Vulnerable › Vulnerabilities

CVE-2026-100351: kin-openapi: ValidationHandler security-requirement bypass via encoded-path operation confusion

• Severity: high (CVSS 7.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-15 · updated 2026-10-15
• Weakness: CWE-289

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 products

• getkin kin-openapi: from 0.144.0, < 0.147.0

References

• https://github.com/getkin/kin-openapi/commit/eda80e2676e9f577ceed2dd80e64f16083edb041
• https://github.com/getkin/kin-openapi/releases/tag/v0.147.0
• https://github.com/getkin/kin-openapi/security/advisories/GHSA-23vg-4cjm-66q5
• https://github.com/getkin/kin-openapi/security/advisories/GHSA-23vg-4cjm-66q5

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