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Backstage: Improper input validation in proxy-backend

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-106491

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-106491

backstage

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

plugin-proxy-backend

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "vendor": "backstage",
    "product": "backstage",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.54.6"
      }
    ]
  },
  {
    "vendor": "@backstage",
    "product": "plugin-proxy-backend",
    "versions": [
      {
        "status": "affected",
        "version": "< 0.6.17"
      }
    ]
  }
]
Related CVEs
CVE-2026-106491

Source reference: /cveMetadata/cveId

Publisher severity

medium

Source reference: /containers/cna/metrics

Event
#12089 · Revision 1
Added to Heist Feed
Publisher date
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