GHSA-9ghw-48h5-v2w5Published

Backstage: Improper input validation in proxy-backend

Exact source revision recorded 24 Oct 2026 13:17:17 UTC. It does not establish the source's current position. Latest evidence.

Recorded JSON

osv · GHSA-9ghw-48h5-v2w5

Published

### Impact 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. ### Patches Patched in `@backstage/plugin-proxy-backend` version `0.6.17` ### Workarounds - Deploy a reverse proxy or WAF in front of Backstage that normalizes request paths before they reach the backend.

Source published: 7 Oct 2026 17:59:49 UTC
Source modified: 7 Oct 2026 18:15:11 UTC
Observed here: 24 Oct 2026 13:17:17 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Publisher rating · MODERATE