[ CVE-2026-106491 · Published 6 Oct 2026 ]
Backstage: Improper input validation in proxy-backend
CVSS 6.4
EPSS <1%Fix available
[ Description ]Official description
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.
[ Fixes ]Fixes and patches
- @backstage/plugin-proxy-backend 0.6.17Fixed version · GitHub Advisories · npm package @backstage/plugin-proxy-backend: upgrade to 0.6.17 or later (affected < 0.6.17)
- Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
- Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
[ Packages ]Affected open-source packages
- @backstage/plugin-proxy-backend npmAffected < 0.6.17 · fixed in 0.6.17 · GHSA-9ghw-48h5-v2w5