CVE-2026-106491

{
  "id": "CVE-2026-106491",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-06T21:17:18.073",
  "lastModified": "2026-10-22T14:10:06.117",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "backstage",
          "product": "backstage",
          "versions": [
            {
              "version": "< 1.54.6",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "@backstage",
          "product": "plugin-proxy-backend",
          "versions": [
            {
              "version": "< 0.6.17",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
          "baseScore": 6.4,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 2.7
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-07T17:51:57.186407Z",
          "id": "CVE-2026-106491",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
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          "operator": "OR",
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  "references": [
    {
      "url": "https://github.com/backstage/backstage/commit/233287d0ce3133e41549bf92a7470c940a41753c",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/backstage/backstage/releases/tag/v1.54.6",
      "source": "[email protected]",
      "tags": [
        "Patch",
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/backstage/backstage/security/advisories/GHSA-9ghw-48h5-v2w5",
      "source": "[email protected]",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ]
    }
  ]
}