CVE-2026-100891 (GCVE-0-2026-100891)

Vulnerability from cvelistv5 – Published: 2026-09-28 00:15 – Updated: 2026-09-28 00:15
VLAI
Title
Trusted Domain Project OpenDMARC Internationalized Domain Name opendmarc_policy.c opendmarc_policy_query_dmarc encoding error
Summary
A vulnerability has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this issue is the function opendmarc_policy_query_dmarc in the library libopendmarc/opendmarc_policy.c of the component Internationalized Domain Name Handler. Such manipulation leads to encoding error. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Severity
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
7.3 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:C
7.3 (High)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:C
CWE
Assigner
References
URL Tags
https://vuldb.com/vuln/410841 vdb-entrytechnical-description
https://vuldb.com/vuln/410841/cti signaturepermissions-required
https://vuldb.com/cve/CVE-2026-100891 third-party-advisory
https://vuldb.com/submit/917215 third-party-advisory
https://weitongli.com/share/opendmarc-ulabel-not-… exploit
Impacted products
Vendor Product Version CPE status
Trusted Domain Project OpenDMARC Affected: 1.4.0
Affected: 1.4.1
Affected: 1.4.2
    cpe:2.3:a:trusted_domain_project:opendmarc:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
WeitongLi (VulDB User) VulDB CNA Team
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "cpes": [
            "cpe:2.3:a:trusted_domain_project:opendmarc:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "Internationalized Domain Name Handler"
          ],
          "product": "OpenDMARC",
          "vendor": "Trusted Domain Project",
          "versions": [
            {
              "status": "affected",
              "version": "1.4.0"
            },
            {
              "status": "affected",
              "version": "1.4.1"
            },
            {
              "status": "affected",
              "version": "1.4.2"
            }
          ]
        }
      ],
      "credits": [
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          "lang": "en",
          "type": "reporter",
          "value": "WeitongLi (VulDB User)"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "VulDB CNA Team"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A vulnerability has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this issue is the function opendmarc_policy_query_dmarc in the library libopendmarc/opendmarc_policy.c of the component Internationalized Domain Name Handler. Such manipulation leads to encoding error. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way."
        }
      ],
      "metrics": [
        {
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      "problemTypes": [
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            {
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      "providerMetadata": {
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        "orgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
        "shortName": "VulDB"
      },
      "references": [
        {
          "name": "VDB-410841 | Trusted Domain Project OpenDMARC Internationalized Domain Name opendmarc_policy.c opendmarc_policy_query_dmarc encoding error",
          "tags": [
            "vdb-entry",
            "technical-description"
          ],
          "url": "https://vuldb.com/vuln/410841"
        },
        {
          "name": "VDB-410841 | CTI Indicators (IOB, IOC, IOA)",
          "tags": [
            "signature",
            "permissions-required"
          ],
          "url": "https://vuldb.com/vuln/410841/cti"
        },
        {
          "name": "CVE-2026-100891 | CVE Analysis and Report",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://vuldb.com/cve/CVE-2026-100891"
        },
        {
          "name": "Submit #917215 | The Trusted Domain Project OpenDMARC 1.4.2 Improper Authentication",
          "tags": [
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          "url": "https://vuldb.com/submit/917215"
        },
        {
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          "url": "https://weitongli.com/share/opendmarc-ulabel-not-converted.html"
        }
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          "time": "2026-09-27T02:00:00.000Z",
          "value": "VulDB entry created"
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          "time": "2026-09-27T10:00:24.000Z",
          "value": "VulDB entry last update"
        }
      ],
      "title": "Trusted Domain Project OpenDMARC Internationalized Domain Name opendmarc_policy.c opendmarc_policy_query_dmarc encoding error",
      "x_generator": [
        "VulDB PVTS v202609"
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
    "assignerShortName": "VulDB",
    "cveId": "CVE-2026-100891",
    "datePublished": "2026-09-28T00:15:14.678Z",
    "dateReserved": "2026-09-27T07:55:14.732Z",
    "dateUpdated": "2026-09-28T00:15:14.678Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-28",
      "epss": "0.00293",
      "percentile": "0.19679"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "cpes": [
                  "cpe:2.3:a:trusted_domain_project:opendmarc:*:*:*:*:*:*:*:*"
                ],
                "modules": [
                  "Internationalized Domain Name Handler"
                ],
                "product": "OpenDMARC",
                "vendor": "Trusted Domain Project",
                "versions": [
                  {
                    "status": "affected",
                    "version": "1.4.0"
                  },
                  {
                    "status": "affected",
                    "version": "1.4.1"
                  },
                  {
                    "status": "affected",
                    "version": "1.4.2"
                  }
                ]
              }
            ],
            "source": "cna@vuldb.com"
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "A vulnerability has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this issue is the function opendmarc_policy_query_dmarc in the library libopendmarc/opendmarc_policy.c of the component Internationalized Domain Name Handler. Such manipulation leads to encoding error. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way."
          }
        ],
        "id": "CVE-2026-100891",
        "lastModified": "2026-09-28T15:15:33.930",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "HIGH",
              "cvssData": {
                "accessComplexity": "LOW",
                "accessVector": "NETWORK",
                "authentication": "NONE",
                "availabilityImpact": "PARTIAL",
                "baseScore": 7.5,
                "confidentialityImpact": "PARTIAL",
                "integrityImpact": "PARTIAL",
                "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
                "version": "2.0"
              },
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              "impactScore": 6.4,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "cna@vuldb.com",
              "type": "Secondary",
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          "cvssMetricV31": [
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            }
          ],
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "availabilityRequirement": "NOT_DEFINED",
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                "exploitMaturity": "PROOF_OF_CONCEPT",
                "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:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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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        "published": "2026-09-28T01:16:28.367",
        "references": [
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      "cve": "CVE-2026-100891",
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      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "opendmarc: Trusted Domain Project OpenDMARC Internationalized Domain Name opendmarc_policy.c opendmarc_policy_query_dmarc encoding error",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100891.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



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