CVE-2026-106491
Medium
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.
SeverityMedium
CVSS6.4
Exploit probability—
Product
Linuxfoundation Backstage
PublishedOct 6, 2026
First seenOct 6, 2026
Weakness typeCWE-20Improper input validationCWE-22Path traversal
How to fix
Update
- linuxfoundation backstage1.54.6 or later
- linuxfoundation backstage\/plugin-proxy-backend0.6.17 or later
- @backstage/plugin-proxy-backend0.6.17 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linuxfoundation backstage | v < 1.54.6 | 1.54.6 |
| linuxfoundation backstage\/plugin-proxy-backend | v < 0.6.17 | 0.6.17 |
| @backstage/plugin-proxy-backendnpm | v < 0.6.17 | 0.6.17 |
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