GHSA-9ghw-48h5-v2w5

Suggest an improvement
Source
https://github.com/advisories/GHSA-9ghw-48h5-v2w5
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-9ghw-48h5-v2w5/GHSA-9ghw-48h5-v2w5.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-9ghw-48h5-v2w5
Aliases
Published
2026-10-07T17:59:49Z
Modified
2026-10-07T18:15:11Z
Severity
  • 6.4 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N CVSS Calculator
Summary
Backstage: Improper input validation in proxy-backend
Details

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.
Database specific 
{
    "cwe_ids": [
        "CWE-20",
        "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-07T17:59:49Z",
    "nvd_published_at": "2026-10-06T21:17:18Z",
    "severity": "MODERATE"
}
References

Affected packages

npm / @backstage/plugin-proxy-backend

Package

Name
@backstage/plugin-proxy-backend
View open source insights on deps.dev
Purl
pkg:npm/%40backstage/plugin-proxy-backend

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
0.6.17

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-9ghw-48h5-v2w5/GHSA-9ghw-48h5-v2w5.json"