FKIE_CVE-2020-26287

Vulnerability from fkie_nvd - Published: 2020-12-29 00:15 - Updated: 2026-06-17 03:08
Severity
8.7 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
8.7 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Summary
HedgeDoc is a collaborative platform for writing and sharing markdown. In HedgeDoc before version 1.7.1 an attacker can inject arbitrary `script` tags in HedgeDoc notes using mermaid diagrams. Our content security policy prevents loading scripts from most locations, but `www.google-analytics.com` is allowed. Using Google Tag Manger it is possible to inject arbitrary JavaScript and execute it on page load. Depending on the configuration of the instance, the attacker may not need authentication to create or edit notes. The problem is patched in HedgeDoc 1.7.1. As a workaround one can disallow `www.google-analytics.com` in the `Content-Security-Policy` header. Note that other ways to leverage the `script` tag injection might exist.
References
security-advisories@github.comhttps://github.com/Alemmi/ctf-writeups/blob/main/hxpctf-2020/hackme/solution.mdExploit, Third Party Advisory
security-advisories@github.comhttps://github.com/hackmdio/codimd/issues/1630Third Party Advisory
security-advisories@github.comhttps://github.com/hedgedoc/hedgedoc/commit/58276ebbf4504a682454a3686dcaff88bc1069d4Patch, Third Party Advisory
security-advisories@github.comhttps://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1Third Party Advisory
security-advisories@github.comhttps://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-g6w6-7xf9-m95pThird Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/Alemmi/ctf-writeups/blob/main/hxpctf-2020/hackme/solution.mdExploit, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/hackmdio/codimd/issues/1630Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/hedgedoc/hedgedoc/commit/58276ebbf4504a682454a3686dcaff88bc1069d4Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-g6w6-7xf9-m95pThird Party Advisory
Impacted products
Vendor Product Version
hedgedoc hedgedoc *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "hedgedoc",
          "vendor": "hedgedoc",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.7.1"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:hedgedoc:hedgedoc:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "DB55BE58-3D3F-40C5-89FE-2AACEA56F4E0",
              "versionEndExcluding": "1.7.1",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "HedgeDoc is a collaborative platform for writing and sharing markdown. In HedgeDoc before version 1.7.1 an attacker can inject arbitrary `script` tags in HedgeDoc notes using mermaid diagrams. Our content security policy prevents loading scripts from most locations, but `www.google-analytics.com` is allowed. Using Google Tag Manger it is possible to inject arbitrary JavaScript and execute it on page load. Depending on the configuration of the instance, the attacker may not need authentication to create or edit notes. The problem is patched in HedgeDoc 1.7.1. As a workaround one can disallow `www.google-analytics.com` in the `Content-Security-Policy` header. Note that other ways to leverage the `script` tag injection might exist."
    },
    {
      "lang": "es",
      "value": "HedgeDoc es una plataforma colaborativa para escribir y compartir rebajas.\u0026#xa0;En HedgeDoc versiones anteriores a 1.7.1, un atacante puede inyectar etiquetas \"script\" arbitrarias en las notas de HedgeDoc usando diagramas mermaid.\u0026#xa0;Nuestra pol\u00edtica de seguridad de contenido evita una carga de scripts de la mayor\u00eda de las ubicaciones, pero se permite \"www.google-analytics.com\"\u0026#xa0;Usando Google Tag Manager, es posible inyectar JavaScript arbitrario y ejecutarlo al cargar la p\u00e1gina.\u0026#xa0;Dependiendo de la configuraci\u00f3n de la instancia, es posible que el atacante no necesite autenticaci\u00f3n para crear o editar notas.\u0026#xa0;El problema est\u00e1 parcheado en HedgeDoc versi\u00f3n 1.7.1.\u0026#xa0;Como soluci\u00f3n alternativa, se puede rechazar \"www.google-analytics.com\" en el encabezado \"Content-Security-Policy\".\u0026#xa0;Tome en cuenta que pueden presentar otras formas de aprovechar la inyecci\u00f3n de etiquetas \"script\""
    }
  ],
  "id": "CVE-2020-26287",
  "lastModified": "2026-06-17T03:08:00.227",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "confidentialityImpact": "NONE",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 8.6,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.3,
        "impactScore": 5.8,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.3,
        "impactScore": 5.8,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2020-12-29T00:15:12.673",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "url": "https://github.com/Alemmi/ctf-writeups/blob/main/hxpctf-2020/hackme/solution.md"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/hackmdio/codimd/issues/1630"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://github.com/hedgedoc/hedgedoc/commit/58276ebbf4504a682454a3686dcaff88bc1069d4"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-g6w6-7xf9-m95p"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "url": "https://github.com/Alemmi/ctf-writeups/blob/main/hxpctf-2020/hackme/solution.md"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/hackmdio/codimd/issues/1630"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://github.com/hedgedoc/hedgedoc/commit/58276ebbf4504a682454a3686dcaff88bc1069d4"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/hedgedoc/hedgedoc/releases/tag/1.7.1"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-g6w6-7xf9-m95p"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.