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CVE-2020-26409

Status: ModifiedMedium (6.5)—

A DOS vulnerability exists in Gitlab CE/EE >=10.3, <13.4.7,>=13.5, <13.5.5,>=13.6, <13.6.2 that allows an attacker to trigger uncontrolled resource by bypassing input validation in markdown fields.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Gitlab — Gitlab

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2020-26409",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:N/I:N/A:P",
          "authentication": "SINGLE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "cve@gitlab.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "cve@gitlab.com",
      "affectedData": [
        {
          "vendor": "GitLab",
          "product": "GitLab CE/EE",
          "versions": [
            {
              "status": "affected",
              "version": ">=10.3"
            },
            {
              "status": "affected",
              "version": "<13.4.7"
            },
            {
              "status": "affected",
              "version": ">=13.5"
            },
            {
              "status": "affected",
              "version": "<13.5.5"
            },
            {
              "status": "affected",
              "version": ">=13.6"
            },
            {
              "status": "affected",
              "version": "<13.6.2"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-12-11T02:15:11.490",
  "references": [
    {
      "url": "https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-26409.json",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "cve@gitlab.com"
    },
    {
      "url": "https://gitlab.com/gitlab-org/gitlab/-/issues/259626",
      "tags": [
        "Broken Link"
      ],
      "source": "cve@gitlab.com"
    },
    {
      "url": "https://hackerone.com/reports/990461",
      "tags": [
        "Permissions Required"
      ],
      "source": "cve@gitlab.com"
    },
    {
      "url": "https://gitlab.com/gitlab-org/cves/-/blob/master/2020/CVE-2020-26409.json",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://gitlab.com/gitlab-org/gitlab/-/issues/259626",
      "tags": [
        "Broken Link"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://hackerone.com/reports/990461",
      "tags": [
        "Permissions Required"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A DOS vulnerability exists in Gitlab CE/EE >=10.3, <13.4.7,>=13.5, <13.5.5,>=13.6, <13.6.2 that allows an attacker to trigger uncontrolled resource by bypassing input validation in markdown fields."
    },
    {
      "lang": "es",
      "value": "Se presenta una vulnerabilidad de DOS en Gitlab CE/EE versiones posteriores a 10.3 incluyéndola, versiones anteriores a 13.4.7, versiones posteriores a 13.5 incluyéndola, versiones anteriores a 13.5.5,  versiones posteriores a 13.6 incluyéndola, versiones anteriores 13.6.2, que permite a un atacante activar un recurso no controlado al omitir la comprobación de entrada en los campos markdown"
    }
  ],
  "lastModified": "2026-06-17T03:08:05.143",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "BD344029-BC42-4233-AA0F-37DC87F8AB1F",
              "versionEndExcluding": "13.4.7",
              "versionStartIncluding": "10.3.0"
            },
            {
              "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "512D9B32-3BDA-49DD-BB42-EAD4270B5FDD",
              "versionEndExcluding": "13.4.7",
              "versionStartIncluding": "10.3.0"
            },
            {
              "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "468AFC4C-4AFE-4502-AE04-CEC567CC9454",
              "versionEndExcluding": "13.5.5",
              "versionStartIncluding": "13.5.0"
            },
            {
              "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C03EE1D3-7824-43A8-ACA2-7EE7EA9B638E",
              "versionEndExcluding": "13.5.5",
              "versionStartIncluding": "13.5.0"
            },
            {
              "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "8A470CCF-C038-44D4-AB14-B9134C0E7ABC",
              "versionEndExcluding": "13.6.2",
              "versionStartIncluding": "13.6.0"
            },
            {
              "criteria": "cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "63A5C9B5-F86B-4066-8042-865AB4DD4859",
              "versionEndExcluding": "13.6.2",
              "versionStartIncluding": "13.6.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@gitlab.com"
}