SB2026081990 - Authentication Bypass by Alternate Name in kin-openapi

CSH
CYBERSECURITY HELP
Sign In REGISTER

Main Vulnerability Database SB2026081990

SB2026081990 - Authentication Bypass by Alternate Name in kin-openapi

Published: August 19, 2026

Security Bulletin ID SB2026081990
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Authentication Bypass by Alternate Name (CVE-ID: N/A)

CWE-ID: CWE-289 - Authentication Bypass by Alternate Name

CVSSv4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass authentication and access a protected handler.

The vulnerability exists due to authentication bypass by alternate name in openapi3filter.ValidationHandler.Middleware when processing requests with encoded paths through a downstream router using different path interpretation semantics. A remote attacker can send a specially crafted request using an encoded path to bypass authentication and access a protected handler.

Exploitation requires the validation layer and downstream router to select different operations for the same request, such as when a public exact route and a protected parameterized route overlap after decoding and use the same HTTP method.


Remediation

Install update from vendor's website.

References