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CVE-2026-8139

Status: AnalyzedLow (2)—

Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via external-link page cvName because updateCollectionAliasExternal bypasses being sanitized. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.0 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N.  Thanks Yonatan Drori (Tenzai) for reporting.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Concretecms — Concrete CMS

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-8139",
  "cveTags": [],
  "metrics": {
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        "ssvcData": {
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          "role": "CISA Coordinator",
          "options": [
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              "exploitation": "none"
            },
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              "automatable": "no"
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              "technicalImpact": "partial"
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          "version": "2.0.3",
          "timestamp": "2026-05-22T12:54:05.104311Z"
        }
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        "source": "nvd@nist.gov",
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          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.7,
        "exploitabilityScore": 2.3
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "ff5b8ace-8b95-4078-9743-eac1ca5451de",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 2,
          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "LOW",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
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          "vulnIntegrityImpact": "LOW",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "NONE",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
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          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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      "source": "ff5b8ace-8b95-4078-9743-eac1ca5451de",
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          "repo": "https://github.com/concretecms/concretecms",
          "vendor": "Concrete CMS",
          "product": "Concrete CMS",
          "versions": [
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              "version": "5.0",
              "versionType": "git",
              "lessThanOrEqual": "9.5.0"
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  ],
  "published": "2026-05-21T22:16:49.533",
  "references": [
    {
      "url": "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "ff5b8ace-8b95-4078-9743-eac1ca5451de"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "ff5b8ace-8b95-4078-9743-eac1ca5451de",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via external-link page cvName because updateCollectionAliasExternal bypasses being sanitized. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.0 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N.  Thanks Yonatan Drori (Tenzai) for reporting."
    },
    {
      "lang": "es",
      "value": "Concrete CMS 9.5.0 y versiones anteriores es vulnerable a XSS Almacenado a través de la página external-link cvName porque updateCollectionAliasExternal omite ser sanitizado. El equipo de seguridad de Concrete CMS otorgó a esta vulnerabilidad una puntuación CVSS v.4.0 de 2.0 con el vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Gracias a Yonatan Drori (Tenzai) por informar."
    }
  ],
  "lastModified": "2026-07-23T16:10:00.137",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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              "versionEndIncluding": "9.5.0"
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          "operator": "OR"
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  "sourceIdentifier": "ff5b8ace-8b95-4078-9743-eac1ca5451de"
}