Vulnerability-Lookup

FKIE_CVE-2026-77751

Vulnerability from fkie_nvd - Published: 2026-08-21 10:16 - Updated: 2026-10-16 15:10

Severity

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

Summary

A path traversal vulnerability existed in the handling of MISP object template names during STIX 2 import and MISP-to-STIX 2 export. MISP object names are passed to PyMISP's object-template resolution mechanism, which constructs a filesystem path by joining the configured MISP object-template directory, the object name, and definition.json. An object name originating from untrusted STIX or MISP content was not sufficiently restricted before being used in this filesystem path. An attacker able to supply a crafted object name containing path separators or traversal sequences such as ../ could therefore cause template resolution to escape the expected template directory and attempt to load a definition.json file from another location accessible to the process. During STIX 2 import, an attacker-controlled x_misp_name from a custom STIX object could directly reach this template-resolution mechanism. The issue could also become persistent. A malicious object name stored in a MISP event could later be processed again during STIX 2 export. Consequently, content originally introduced in one security context could trigger filesystem access later when the event is exported by a process operating with different or greater privileges. If a suitable definition.json file exists outside the intended template directory, its contents may be interpreted as a MISP object template and fields from that file copied into the converted object. This can result in unintended disclosure of locally accessible data represented by the template file and modification of the resulting object's metadata or semantics. The patches introduce strict validation of object-template names. Valid names are restricted to a single path component containing letters, digits, hyphens, or underscores. Names that do not meet these requirements are replaced with the generic unknown-template name before reaching PyMISP template resolution. The original rejected name is preserved in the object's comment and a warning is generated, preventing traversal while retaining the source information.

References

	URL	Tags
	5a6e4751-2f3f-4070-9419-94fb35b644e8	https://github.com/MISP/misp-stix/commit/a0f54070
	5a6e4751-2f3f-4070-9419-94fb35b644e8	https://github.com/MISP/misp-stix/commit/a8b6808d

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "misp-stix",
          "repo": "https://github.com/MISP/misp-stix/",
          "vendor": "misp",
          "versions": [
            {
              "lessThanOrEqual": "2026.7.8",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "A path traversal vulnerability existed in the handling of MISP object template names during STIX 2 import and MISP-to-STIX 2 export.\n\nMISP object names are passed to PyMISP\u0027s object-template resolution mechanism, which constructs a filesystem path by joining the configured MISP object-template directory, the object name, and definition.json. An object name originating from untrusted STIX or MISP content was not sufficiently restricted before being used in this filesystem path.\n\nAn attacker able to supply a crafted object name containing path separators or traversal sequences such as ../ could therefore cause template resolution to escape the expected template directory and attempt to load a definition.json file from another location accessible to the process.\n\nDuring STIX 2 import, an attacker-controlled x_misp_name from a custom STIX object could directly reach this template-resolution mechanism.\n\nThe issue could also become persistent. A malicious object name stored in a MISP event could later be processed again during STIX 2 export. Consequently, content originally introduced in one security context could trigger filesystem access later when the event is exported by a process operating with different or greater privileges.\n\nIf a suitable definition.json file exists outside the intended template directory, its contents may be interpreted as a MISP object template and fields from that file copied into the converted object. This can result in unintended disclosure of locally accessible data represented by the template file and modification of the resulting object\u0027s metadata or semantics.\n\nThe patches introduce strict validation of object-template names. Valid names are restricted to a single path component containing letters, digits, hyphens, or underscores. Names that do not meet these requirements are replaced with the generic unknown-template name before reaching PyMISP template resolution. The original rejected name is preserved in the object\u0027s comment and a warning is generated, preventing traversal while retaining the source information."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de salto de ruta exist\u00eda en el manejo de los nombres de las plantillas de objetos MISP durante la importaci\u00f3n de STIX 2 y la exportaci\u00f3n de MISP a STIX 2.\n\nLos nombres de objetos MISP se pasan al mecanismo de resoluci\u00f3n de plantillas de objetos de PyMISP, el cual construye una ruta del sistema de archivos uniendo el directorio configurado de plantillas de objetos MISP, el nombre del objeto y definition.json. Un nombre de objeto originado de contenido STIX o MISP no confiable no estaba suficientemente restringido antes de ser usado en esta ruta del sistema de archivos.\n\nUn atacante capaz de proporcionar un nombre de objeto manipulado que contenga separadores de ruta o secuencias de salto de ruta como ../ podr\u00eda por lo tanto causar que la resoluci\u00f3n de la plantilla escape del directorio de plantillas esperado e intente cargar un archivo definition.json desde otra ubicaci\u00f3n accesible para el proceso.\n\nDurante la importaci\u00f3n de STIX 2, un x_misp_name controlado por el atacante de un objeto STIX personalizado podr\u00eda alcanzar directamente este mecanismo de resoluci\u00f3n de plantillas.\n\nEl problema tambi\u00e9n podr\u00eda volverse persistente. Un nombre de objeto malicioso almacenado en un evento MISP podr\u00eda ser procesado de nuevo m\u00e1s tarde durante la exportaci\u00f3n de STIX 2. En consecuencia, el contenido introducido originalmente en un contexto de seguridad podr\u00eda desencadenar acceso al sistema de archivos m\u00e1s tarde cuando el evento es exportado por un proceso que opera con privilegios diferentes o mayores.\n\nSi existe un archivo definition.json adecuado fuera del directorio de plantillas previsto, su contenido puede ser interpretado como una plantilla de objeto MISP y los campos de ese archivo copiados en el objeto convertido. Esto puede resultar en la divulgaci\u00f3n no intencionada de datos accesibles localmente representados por el archivo de plantilla y la modificaci\u00f3n de los metadatos o la sem\u00e1ntica del objeto resultante.\n\nLos parches introducen una validaci\u00f3n estricta de los nombres de las plantillas de objetos. Los nombres v\u00e1lidos est\u00e1n restringidos a un \u00fanico componente de ruta que contenga letras, d\u00edgitos, guiones o guiones bajos. Los nombres que no cumplen estos requisitos se reemplazan con el nombre gen\u00e9rico unknown-template antes de llegar a la resoluci\u00f3n de plantillas de PyMISP. El nombre original rechazado se conserva en el comentario del objeto y se genera una advertencia, lo que evita el salto de ruta mientras se retiene la informaci\u00f3n de origen."
    }
  ],
  "id": "CVE-2026-77751",
  "lastModified": "2026-10-16T15:10:00.103",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "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:H/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": "HIGH",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-77751",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-25T19:08:15.945042Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-21T10:16:39.210",
  "references": [
    {
      "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
      "url": "https://github.com/MISP/misp-stix/commit/a0f54070"
    },
    {
      "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
      "url": "https://github.com/MISP/misp-stix/commit/a8b6808d"
    }
  ],
  "sourceIdentifier": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ],
      "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
      "type": "Secondary"
    }
  ]
}

CVE-2026-77751 (GCVE-0-2026-77751)

Vulnerability from cvelistv5 – Published: 2026-08-21 09:48 – Updated: 2026-08-25 19:08

Title

Path Traversal in MISP Object Template Resolution During STIX Import and Export in misp-stix library

Summary

Severity

8.8 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 19:08 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

CIRCL CNA under the ENISA root

CNA scorecard A 90/100 over 243 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/MISP/misp-stix/commit/a8b6808d	patch
https://github.com/MISP/misp-stix/commit/a0f54070	patch

Impacted products

1 product

Vendor	Product	Version
misp	misp-stix	Affected: 0 , ≤ 2026.7.8 (semver)

Credits

Christian Studer 🕵️‍♂️ Jeroen Pinoy 🐞

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-77751",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-25T19:08:15.945042Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-25T19:08:25.414Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "misp-stix",
          "repo": "https://github.com/MISP/misp-stix/",
          "vendor": "misp",
          "versions": [
            {
              "lessThanOrEqual": "2026.7.8",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Christian Studer"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Jeroen Pinoy"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eA path traversal vulnerability existed in the handling of MISP object template names during STIX 2 import and MISP-to-STIX 2 export.\u003c/p\u003e\u003cp\u003eMISP object names are passed to PyMISP\u0027s object-template resolution mechanism, which constructs a filesystem path by joining the configured MISP object-template directory, the object name, and \u003ccode\u003edefinition.json\u003c/code\u003e. An object name originating from untrusted STIX or MISP content was not sufficiently restricted before being used in this filesystem path.\u003c/p\u003e\u003cp\u003eAn attacker able to supply a crafted object name containing path separators or traversal sequences such as \u003ccode\u003e../\u003c/code\u003e could therefore cause template resolution to escape the expected template directory and attempt to load a \u003ccode\u003edefinition.json\u003c/code\u003e file from another location accessible to the process.\u003c/p\u003e\u003cp\u003eDuring \u003cstrong\u003eSTIX 2 import\u003c/strong\u003e, an attacker-controlled \u003ccode\u003ex_misp_name\u003c/code\u003e from a custom STIX object could directly reach this template-resolution mechanism.\u003c/p\u003e\u003cp\u003eThe issue could also become \u003cstrong\u003epersistent\u003c/strong\u003e. A malicious object name stored in a MISP event could later be processed again during STIX 2 export. Consequently, content originally introduced in one security context could trigger filesystem access later when the event is exported by a process operating with different or greater privileges.\u003c/p\u003e\u003cp\u003eIf a suitable \u003ccode\u003edefinition.json\u003c/code\u003e file exists outside the intended template directory, its contents may be interpreted as a MISP object template and fields from that file copied into the converted object. This can result in unintended disclosure of locally accessible data represented by the template file and modification of the resulting object\u0027s metadata or semantics.\u003c/p\u003e\u003cp\u003eThe patches introduce strict validation of object-template names. Valid names are restricted to a single path component containing letters, digits, hyphens, or underscores. Names that do not meet these requirements are replaced with the generic \u003ccode\u003eunknown-template\u003c/code\u003e name before reaching PyMISP template resolution. The original rejected name is preserved in the object\u0027s comment and a warning is generated, preventing traversal while retaining the source information.\u003c/p\u003e\u003cbr\u003e"
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          ],
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      "impacts": [
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      "metrics": [
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            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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              "type": "CWE"
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          "url": "https://github.com/MISP/misp-stix/commit/a8b6808d"
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          "tags": [
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          "url": "https://github.com/MISP/misp-stix/commit/a0f54070"
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      "source": {
        "discovery": "EXTERNAL"
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      "title": "Path Traversal in MISP Object Template Resolution During STIX Import and Export in misp-stix library",
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    "datePublished": "2026-08-21T09:48:20.168Z",
    "dateReserved": "2026-08-21T09:48:16.206Z",
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    "state": "PUBLISHED"
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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.

Vulnerability timeline

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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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