FKIE_CVE-2026-106457

Vulnerability from fkie_nvd - Published: 2026-10-06 21:17 - Updated: 2026-10-07 16:17
Severity
6.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Summary
Backstage is an open framework for building developer portals. From 0.1.0 until 0.5.0, the @backstage/plugin-auth-backend-module-cloudflare-access-provider package is affected by insufficient audience validation in the cloudflare access auth provider. The Cloudflare Access auth provider verifies a token's signature and team issuer, but affected versions do not verify that the token was issued for the Backstage application. A user holding a valid token for another Access application in the same Cloudflare Zero Trust team may therefore be able to authenticate to Backstage if that token reaches the auth endpoint without the Backstage application's audience already being enforced upstream. Cloudflare Access normally evaluates the protected application before forwarding requests. This issue is fixed in version 0.5.0.
References
security-advisories@github.comhttps://github.com/backstage/backstage/commit/ed9034cacd9def3b3674f0a764fe992f751e204d
security-advisories@github.comhttps://github.com/backstage/backstage/releases/tag/v1.55.0
security-advisories@github.comhttps://github.com/backstage/backstage/security/advisories/GHSA-q333-f498-w2x7
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "backstage",
          "vendor": "backstage",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.26.0, \u003c 1.55.0"
            }
          ]
        },
        {
          "product": "plugin-auth-backend-module-cloudflare-access-provider",
          "vendor": "@backstage",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.1.0, \u003c 0.5.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Backstage is an open framework for building developer portals. From 0.1.0 until 0.5.0, the @backstage/plugin-auth-backend-module-cloudflare-access-provider package is affected by insufficient audience validation in the cloudflare access auth provider. The Cloudflare Access auth provider verifies a token\u0027s signature and team issuer, but affected versions do not verify that the token was issued for the Backstage application. A user holding a valid token for another Access application in the same Cloudflare Zero Trust team may therefore be able to authenticate to Backstage if that token reaches the auth endpoint without the Backstage application\u0027s audience already being enforced upstream. Cloudflare Access normally evaluates the protected application before forwarding requests. This issue is fixed in version 0.5.0."
    }
  ],
  "id": "CVE-2026-106457",
  "lastModified": "2026-10-07T16:17:38.710",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-106457",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-07T15:06:22.900061Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-06T21:17:16.083",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/backstage/backstage/commit/ed9034cacd9def3b3674f0a764fe992f751e204d"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/backstage/backstage/releases/tag/v1.55.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/backstage/backstage/security/advisories/GHSA-q333-f498-w2x7"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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