Vulnerability-Lookup

CVE-2026-54721 (GCVE-0-2026-54721)

Vulnerability from cvelistv5 – Published: 2026-08-27 16:52 – Updated: 2026-08-27 16:52

Title

Silverstripe UserForms: Remote code execution via userforms email subject

Summary

Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with permission to configure a UserForms email recipient can use the subject field to run arbitrary code on the server, compromising confidentiality, integrity, and availability. This issue is fixed in versions 6.4.9, 7.0.7, and 7.1.1.

Severity

8.8 (High)


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

CWE

CWE-94 - Improper Control of Generation of Code ('Code Injection')

Assigner

GitHub_M mitre root

References

8 references

URL	Tags
https://github.com/silverstripe/silverstripe-user…	x_refsource_CONFIRM
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC
https://github.com/silverstripe/silverstripe-user…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
silverstripe	silverstripe-userforms	Affected: < 6.4.9 Affected: >= 7.0.0, < 7.0.7 Affected: >= 7.1.0, < 7.1.1	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "silverstripe-userforms",
          "vendor": "silverstripe",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.4.9"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.0.0, \u003c 7.0.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.1.0, \u003c 7.1.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with permission to configure a UserForms email recipient can use the subject field to run arbitrary code on the server, compromising confidentiality, integrity, and availability. This issue is fixed in versions 6.4.9, 7.0.7, and 7.1.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94: Improper Control of Generation of Code (\u0027Code Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T16:52:46.023Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/pull/1441",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/pull/1441"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/pull/1442",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/pull/1442"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7"
        },
        {
          "name": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1"
        }
      ],
      "source": {
        "advisory": "GHSA-g8wr-r2v2-vqc6",
        "discovery": "UNKNOWN"
      },
      "title": "Silverstripe UserForms: Remote code execution via userforms email subject"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54721",
    "datePublished": "2026-08-27T16:52:46.023Z",
    "dateReserved": "2026-06-15T23:07:33.231Z",
    "dateUpdated": "2026-08-27T16:52:46.023Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-54721\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-27T20:17:49.973\",\"lastModified\":\"2026-08-27T20:17:49.973\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with permission to configure a UserForms email recipient can use the subject field to run arbitrary code on the server, compromising confidentiality, integrity, and availability. This issue is fixed in versions 6.4.9, 7.0.7, and 7.1.1.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"silverstripe\",\"product\":\"silverstripe-userforms\",\"versions\":[{\"version\":\"\u003c 6.4.9\",\"status\":\"affected\"},{\"version\":\"\u003e= 7.0.0, \u003c 7.0.7\",\"status\":\"affected\"},{\"version\":\"\u003e= 7.1.0, \u003c 7.1.1\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-94\"}]}],\"references\":[{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/pull/1441\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/pull/1442\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}

FKIE_CVE-2026-54721

Vulnerability from fkie_nvd - Published: 2026-08-27 20:17 - Updated: 2026-08-27 20:17

Severity

8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/pull/1441
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/pull/1442
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1
	security-advisories@github.com	https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "silverstripe-userforms",
          "vendor": "silverstripe",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.4.9"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.0.0, \u003c 7.0.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.1.0, \u003c 7.1.1"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with permission to configure a UserForms email recipient can use the subject field to run arbitrary code on the server, compromising confidentiality, integrity, and availability. This issue is fixed in versions 6.4.9, 7.0.7, and 7.1.1."
    }
  ],
  "id": "CVE-2026-54721",
  "lastModified": "2026-08-27T20:17:49.973",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-27T20:17:49.973",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/pull/1441"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/pull/1442"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-94"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

GHSA-G8WR-R2V2-VQC6

Vulnerability from github – Published: 2026-08-27 16:53 – Updated: 2026-08-27 16:53

Summary

silverstripe/userforms vulnerable to remote code execution via userforms email subject

Details

Impact

The userform email subject field in the CMS is vulnerable to a specially crafted payload being used to run arbitrary code on the server.

Reported by

Jack Wallace from Bastion Security

Severity

8.8 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "silverstripe/userforms"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.4.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "silverstripe/userforms"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.0.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "silverstripe/userforms"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.1.0"
            },
            {
              "fixed": "7.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54721"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-27T16:53:17Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Impact\nThe userform email subject field in the CMS is vulnerable to a specially crafted payload being used to run arbitrary code on the server.\n\n### Reported by\nJack Wallace from Bastion Security",
  "id": "GHSA-g8wr-r2v2-vqc6",
  "modified": "2026-08-27T16:53:18Z",
  "published": "2026-08-27T16:53:17Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/pull/1441"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/pull/1442"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/userforms/CVE-2026-54721.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/silverstripe/silverstripe-userforms"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1"
    },
    {
      "type": "WEB",
      "url": "https://www.silverstripe.org/download/security-releases/cve-2026-54721"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "silverstripe/userforms vulnerable to remote code execution via userforms email subject"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-54721 (GCVE-0-2026-54721)

FKIE_CVE-2026-54721

GHSA-G8WR-R2V2-VQC6

Impact

Reported by

Tags

Sightings

Nomenclature