Vulnerability Details CVE-2026-106491
Backstage is an open framework for building developer portals. Prior to 0.6.17, the @backstage/plugin-proxy-backend package is affected by improper input validation in proxy-backend. An authenticated Backstage user could craft a request URL that causes the proxy-backend to forward the request to a path outside the configured base path on the target server. This is limited to target servers already configured as proxy endpoints and requires Backstage authentication by default. This issue is fixed in version 0.6.17.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 17.7%
CVSS Severity
CVSS v3 Score 6.4