Vulnerability-Lookup

CVE-2026-75872 (GCVE-0-2026-75872)

Vulnerability from cvelistv5 – Published: 2026-08-18 14:06 – Updated: 2026-08-18 16:04 X_Open Source

Title

HTML Injection in MailerUp double opt-in verification email

Summary

HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner's configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email.

Severity

6.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-18 16:04 UTC

CWE

CWE-80 - Improper neutralization of Script-Related HTML tags in a web page (basic XSS)

Assigner

Secur0 INCIBE root

References

3 references

URL	Tags
https://github.com/maalfer/mailerup/commit/da4aed…	patch
https://github.com/maalfer/mailerup/releases/tag/v1.1.3	release-notes
https://secur0.com/en/cna/cve-list/cve-2026-75872…	technical-description

Impacted products

1 product

Vendor	Product	Version	CPE status
maalfer	MailerUp	Affected: 0 , < 1.1.3 (semver) cpe:2.3:a:maalfer:mailerup::::::::

Date Public

2026-08-18 12:43

Credits

Nacho García Egea Xoán M. Otero Jorge Secur0 CNA Mario Álvarez Fernández

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-75872",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-18T16:04:23.484003Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-18T16:04:29.499Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "modules": [
            "Public subscription form"
          ],
          "product": "MailerUp",
          "programFiles": [
            "backend/apps/forms/views.py"
          ],
          "repo": "https://github.com/maalfer/mailerup",
          "vendor": "maalfer",
          "versions": [
            {
              "lessThan": "1.1.3",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:maalfer:mailerup:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "1.1.3",
                  "versionStartIncluding": "0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "OR"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Nacho Garc\u00eda Egea"
        },
        {
          "lang": "en",
          "type": "analyst",
          "value": "Xo\u00e1n M. Otero Jorge"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Secur0 CNA"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Mario \u00c1lvarez Fern\u00e1ndez"
        }
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      "datePublic": "2026-08-18T12:43:00.000Z",
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            {
              "base64": false,
              "type": "text/html",
              "value": "HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner\u0027s configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email."
            }
          ],
          "value": "HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner\u0027s configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-242",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-242 Code Injection"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
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            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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          "scenarios": [
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              "value": "GENERAL"
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      "problemTypes": [
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          "descriptions": [
            {
              "cweId": "CWE-80",
              "description": "CWE-80 Improper neutralization of Script-Related HTML tags in a web page (basic XSS)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-18T14:06:37.102Z",
        "orgId": "4daa8cea-433a-44bd-9456-53b127fc289a",
        "shortName": "Secur0"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/maalfer/mailerup/commit/da4aedc9621911df4ce0cc8f0b321dd6d10f40a5"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/maalfer/mailerup/releases/tag/v1.1.3"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://secur0.com/en/cna/cve-list/cve-2026-75872-html-injection-in-mailerup-double-optin-verification-email"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cstrong\u003e\u003c/strong\u003e Upgrade to version 1.1.3 or higher."
            }
          ],
          "value": "Upgrade to version 1.1.3 or higher."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "tags": [
        "x_open-source"
      ],
      "title": "HTML Injection in MailerUp double opt-in verification email",
      "x_generator": {
        "engine": "Vulnogram 1.0.4"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "4daa8cea-433a-44bd-9456-53b127fc289a",
    "assignerShortName": "Secur0",
    "cveId": "CVE-2026-75872",
    "datePublished": "2026-08-18T14:06:37.102Z",
    "dateReserved": "2026-08-18T12:20:39.352Z",
    "dateUpdated": "2026-08-18T16:04:29.499Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-75872\",\"sourceIdentifier\":\"4daa8cea-433a-44bd-9456-53b127fc289a\",\"published\":\"2026-08-18T15:17:15.150\",\"lastModified\":\"2026-08-18T16:18:21.930\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner\u0027s configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email.\"}],\"affected\":[{\"source\":\"4daa8cea-433a-44bd-9456-53b127fc289a\",\"affectedData\":[{\"vendor\":\"maalfer\",\"product\":\"MailerUp\",\"defaultStatus\":\"unaffected\",\"modules\":[\"Public subscription form\"],\"programFiles\":[\"backend/apps/forms/views.py\"],\"repo\":\"https://github.com/maalfer/mailerup\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"1.1.3\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"4daa8cea-433a-44bd-9456-53b127fc289a\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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\",\"baseScore\":6.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"LOW\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-08-18T16:04:23.484003Z\",\"id\":\"CVE-2026-75872\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"4daa8cea-433a-44bd-9456-53b127fc289a\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-80\"}]}],\"references\":[{\"url\":\"https://github.com/maalfer/mailerup/commit/da4aedc9621911df4ce0cc8f0b321dd6d10f40a5\",\"source\":\"4daa8cea-433a-44bd-9456-53b127fc289a\"},{\"url\":\"https://github.com/maalfer/mailerup/releases/tag/v1.1.3\",\"source\":\"4daa8cea-433a-44bd-9456-53b127fc289a\"},{\"url\":\"https://secur0.com/en/cna/cve-list/cve-2026-75872-html-injection-in-mailerup-double-optin-verification-email\",\"source\":\"4daa8cea-433a-44bd-9456-53b127fc289a\"}]}}"
  }
}

FKIE_CVE-2026-75872

Vulnerability from fkie_nvd - Published: 2026-08-18 15:17 - Updated: 2026-08-18 16:18

Severity

6.9 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Summary

References

	URL	Tags
	4daa8cea-433a-44bd-9456-53b127fc289a	https://github.com/maalfer/mailerup/commit/da4aedc9621911df4ce0cc8f0b321dd6d10f40a5
	4daa8cea-433a-44bd-9456-53b127fc289a	https://github.com/maalfer/mailerup/releases/tag/v1.1.3
	4daa8cea-433a-44bd-9456-53b127fc289a	https://secur0.com/en/cna/cve-list/cve-2026-75872-html-injection-in-mailerup-double-optin-verification-email

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "modules": [
            "Public subscription form"
          ],
          "product": "MailerUp",
          "programFiles": [
            "backend/apps/forms/views.py"
          ],
          "repo": "https://github.com/maalfer/mailerup",
          "vendor": "maalfer",
          "versions": [
            {
              "lessThan": "1.1.3",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner\u0027s configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email."
    }
  ],
  "id": "CVE-2026-75872",
  "lastModified": "2026-08-18T16:18:21.930",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-75872",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-18T16:04:23.484003Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-18T15:17:15.150",
  "references": [
    {
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
      "url": "https://github.com/maalfer/mailerup/commit/da4aedc9621911df4ce0cc8f0b321dd6d10f40a5"
    },
    {
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
      "url": "https://github.com/maalfer/mailerup/releases/tag/v1.1.3"
    },
    {
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
      "url": "https://secur0.com/en/cna/cve-list/cve-2026-75872-html-injection-in-mailerup-double-optin-verification-email"
    }
  ],
  "sourceIdentifier": "4daa8cea-433a-44bd-9456-53b127fc289a",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-80"
        }
      ],
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
      "type": "Secondary"
    }
  ]
}

GHSA-GJ4P-RXXG-6JHM

Vulnerability from github – Published: 2026-08-18 15:31 – Updated: 2026-08-18 15:31

Details

Severity

6.9 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-75872"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-80"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-18T15:17:15Z",
    "severity": "MODERATE"
  },
  "details": "HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner\u0027s configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email.",
  "id": "GHSA-gj4p-rxxg-6jhm",
  "modified": "2026-08-18T15:31:49Z",
  "published": "2026-08-18T15:31:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-75872"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maalfer/mailerup/commit/da4aedc9621911df4ce0cc8f0b321dd6d10f40a5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/maalfer/mailerup/releases/tag/v1.1.3"
    },
    {
      "type": "WEB",
      "url": "https://secur0.com/en/cna/cve-list/cve-2026-75872-html-injection-in-mailerup-double-optin-verification-email"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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",
      "type": "CVSS_V4"
    }
  ]
}

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-2026-75872 (GCVE-0-2026-75872)

FKIE_CVE-2026-75872

GHSA-GJ4P-RXXG-6JHM

Tags

Sightings

Nomenclature