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CVE-2021-21686

Status: ModifiedHigh (8.1)—

File path filters in the agent-to-controller security subsystem of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier do not canonicalize paths, allowing operations to follow symbolic links to outside allowed directories.

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)

Jenkins — Jenkins

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-21686",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5.8,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:N",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 4.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.1,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "jenkinsci-cert@googlegroups.com",
      "affectedData": [
        {
          "vendor": "Jenkins project",
          "product": "Jenkins",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom",
              "lessThanOrEqual": "2.318"
            },
            {
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom",
              "lessThanOrEqual": "LTS 2.303.2"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-11-04T17:15:08.277",
  "references": [
    {
      "url": "https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2455",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "jenkinsci-cert@googlegroups.com"
    },
    {
      "url": "https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2455",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-59"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "File path filters in the agent-to-controller security subsystem of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier do not canonicalize paths, allowing operations to follow symbolic links to outside allowed directories."
    },
    {
      "lang": "es",
      "value": "Los filtros de rutas de archivos en el subsistema de seguridad agente-a-controlador de Jenkins versiones 2.318 y anteriores, LTS versiones 2.303.2 y anteriores, no canonizan las rutas, permitiendo que las operaciones sigan enlaces simbólicos a directorios no permitidos"
    }
  ],
  "lastModified": "2026-06-17T03:35:59.793",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:jenkins:jenkins:*:*:*:*:lts:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0B0C915B-C3A9-4BB9-B122-749CF43BB7DE",
              "versionEndExcluding": "2.303.3"
            },
            {
              "criteria": "cpe:2.3:a:jenkins:jenkins:*:*:*:*:-:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3D231DBA-462F-4BC5-8F04-23109A7EF1F8",
              "versionEndExcluding": "2.319"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "jenkinsci-cert@googlegroups.com"
}