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.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/backstage/backstage/commit/233287d0ce3133e41549bf92a7470c940a41753c Patch
- https://github.com/backstage/backstage/releases/tag/v1.54.6 Patch, Release Notes
- https://github.com/backstage/backstage/security/advisories/GHSA-9ghw-48h5-v2w5 Mitigation, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.4 · linuxfoundationNVD modified 2026-10-22 14:10
Affected (CPE criteria) 2
cpe:2.3:a:linuxfoundation:backstage\/plugin-proxy-backend:*:*:*:*:*:node.js:*:*cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:*