CVE-2026-106491
Backstage: Improper input validation in proxy-backend
CVSS Score
6.4
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-20 CWE-22 |
| Vendor | backstage |
| Product | backstage |
| Published | Oct 6, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
backstage / backstage
< 1.54.6
@backstage / plugin-proxy-backend
< 0.6.17