Vulnerability-Lookup

GHSA-645J-CM4X-3XVW

Vulnerability from github – Published: 2026-05-21 21:30 – Updated: 2026-05-26 21:31

Details

Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader's extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in authenticated remote code execution. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H Thanks Yonatan Drori (Tenzai) for reporting.

Severity

7.2 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

9.4 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-8134"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-23"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-21T21:16:32Z",
    "severity": "CRITICAL"
  },
  "details": "Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader\u0027s extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in\u00a0authenticated remote code execution.\u00a0The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector\u00a0CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H\u00a0 \u00a0Thanks\u00a0Yonatan Drori\u00a0(Tenzai)\u00a0for reporting.",
  "id": "GHSA-645j-cm4x-3xvw",
  "modified": "2026-05-26T21:31:37Z",
  "published": "2026-05-21T21:30:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-8134"
    },
    {
      "type": "WEB",
      "url": "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-8134 (GCVE-0-2026-8134)

Vulnerability from cvelistv5 – Published: 2026-05-21 20:13 – Updated: 2026-05-22 12:15

Title

Concrete CMS 9.5.0 and below is vulnerable to Authenticated RCE via Composer customTemplate Path Traversal leading to PHP File Inclusion

Summary

Severity

9.4 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CWE

CWE-98 - Improper control of filename for Include/Require statement in PHP program ('PHP remote file inclusion')
CWE-434 - Unrestricted upload of file with dangerous type
CWE-23 - Relative path traversal

Assigner

ConcreteCMS

References

1 reference

URL	Tags
https://documentation.concretecms.org/9-x/develop…	release-notes

Impacted products

1 product

Vendor	Product	Version
Concrete CMS	Concrete CMS	Affected: 5.0 , ≤ 9.5.0 (git)

Credits

Yonatan Drori (Tenzai)

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-8134",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-22T12:15:06.851749Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-22T12:15:15.179Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://github.com/concretecms/concretecms",
          "defaultStatus": "unaffected",
          "product": "Concrete CMS",
          "programFiles": [
            "https://github.com/concretecms/concretecms"
          ],
          "repo": "https://github.com/concretecms/concretecms",
          "vendor": "Concrete CMS",
          "versions": [
            {
              "lessThanOrEqual": "9.5.0",
              "status": "affected",
              "version": "5.0",
              "versionType": "git"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Yonatan Drori (Tenzai)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cdiv\u003eConcrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the \u003ccode\u003eptComposerFormLayoutSetControlCustomTemplate\u003c/code\u003e field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader\u0027s extension-only validation (which permits PHP code in files saved with image extensions like \u003ccode\u003e.png\u003c/code\u003e), this can result in\u0026nbsp;authenticated remote code execution.\u0026nbsp;The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector\u0026nbsp;CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H\u0026nbsp; \u0026nbsp;Thanks\u0026nbsp;\u003cspan\u003eYonatan Drori\u0026nbsp;\u003c/span\u003e(Tenzai)\u0026nbsp;\u003cspan\u003efor reporting.\u0026nbsp;\u003c/span\u003e\u003c/div\u003e"
            }
          ],
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        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-252",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-252 PHP Local File Inclusion"
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          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 9.4,
            "baseSeverity": "CRITICAL",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "HIGH",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "HIGH",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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              "type": "CWE"
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        },
        {
          "descriptions": [
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              "cweId": "CWE-434",
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              "type": "CWE"
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          ]
        },
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          "descriptions": [
            {
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              "description": "CWE-23 Relative path traversal",
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          "tags": [
            "release-notes"
          ],
          "url": "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"
        }
      ],
      "source": {
        "defect": [
          "HackerOne"
        ],
        "discovery": "UNKNOWN"
      },
      "title": "Concrete CMS 9.5.0 and below is vulnerable to Authenticated RCE via Composer customTemplate Path Traversal leading to PHP File Inclusion",
      "x_generator": {
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  },
  "cveMetadata": {
    "assignerOrgId": "ff5b8ace-8b95-4078-9743-eac1ca5451de",
    "assignerShortName": "ConcreteCMS",
    "cveId": "CVE-2026-8134",
    "datePublished": "2026-05-21T20:13:31.343Z",
    "dateReserved": "2026-05-07T17:49:33.331Z",
    "dateUpdated": "2026-05-22T12:15:15.179Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-645J-CM4X-3XVW

CVE-2026-8134 (GCVE-0-2026-8134)

Tags

Sightings

Nomenclature