CVE-2026-106491 · GHSA-9ghw-48h5-v2w5
Backstage: Improper input validation in proxy-backend
- Risk score
- 47/100
- CVSS
- 6.4 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 6 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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 con…
- Affected
- @backstage/plugin-proxy-backend (npm) < 0.6.17
- Fix
- Upgrade @backstage/plugin-proxy-backend to 0.6.17 or later.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 6.4 medium
- On your watchlist: npm
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| @backstage/plugin-proxy-backend | npm | < 0.6.17 | 0.6.17 |
References
- https://github.com/advisories/GHSA-9ghw-48h5-v2w5
- https://github.com/backstage/backstage/security/advisories/GHSA-9ghw-48h5-v2w5
- https://nvd.nist.gov/vuln/detail/CVE-2026-106491
- https://github.com/backstage/backstage/commit/233287d0ce3133e41549bf92a7470c940a41753c
- https://github.com/backstage/backstage/releases/tag/v1.54.6
- https://github.com/advisories/GHSA-9ghw-48h5-v2w5
Original 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.
Last activity 6 Oct 2026. Patch Forecast updates every hour.