CVE-2020-28169

Status: ModifiedHigh (7)—💥 Exploit

The td-agent-builder plugin before 2020-12-18 for Fluentd allows attackers to gain privileges because the bin directory is writable by a user account, but a file in bin is executed as NT AUTHORITY\SYSTEM.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 1.17%
Percentile among all scored CVEs: 67
Score date: 10/9/2026

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).

💥 Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

Published on Exploit-DB · Fluentd TD-agent plugin 4.0.1 - Insecure Folder Permission (1/5/2021)
Proof of concept on GitHub (unverified) · List of proofs of concept on GitHub

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

Affected technologies (2)

Debian — Debian Linux Td-agent-builder Project — Td-agent-builder

CWEs

CWE-732

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2020-28169",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 6.9,
          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:M/Au:N/C:C/I:C/A:C",
          "authentication": "NONE",
          "integrityImpact": "COMPLETE",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "COMPLETE",
          "confidentialityImpact": "COMPLETE"
        },
        "acInsufInfo": false,
        "impactScore": 10,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 3.4,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-12-24T15:15:12.950",
  "references": [
    {
      "url": "http://packetstormsecurity.com/files/160791/Fluentd-TD-agent-4.0.1-Insecure-Folder-Permission.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://docs.fluentd.org/installation/install-by-msi",
      "tags": [
        "Product",
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/fluent-plugins-nursery/td-agent-builder/pull/247/commits/6f9cb6393392d62caa99907c0ebbcbab6b94a3f1",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/fluent/fluentd/issues/3201",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/kenhys/td-agent-builder/commit/eec6e2dedf12f2e0c01c2bbe7b8c15b639b3b938",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://td-agent-package-browser.herokuapp.com/4/windows",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://www.debian.org/security/2021/dsa-4949",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://www.fluentd.org/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://packetstormsecurity.com/files/160791/Fluentd-TD-agent-4.0.1-Insecure-Folder-Permission.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://docs.fluentd.org/installation/install-by-msi",
      "tags": [
        "Product",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/fluent-plugins-nursery/td-agent-builder/pull/247/commits/6f9cb6393392d62caa99907c0ebbcbab6b94a3f1",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/fluent/fluentd/issues/3201",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/kenhys/td-agent-builder/commit/eec6e2dedf12f2e0c01c2bbe7b8c15b639b3b938",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://td-agent-package-browser.herokuapp.com/4/windows",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.debian.org/security/2021/dsa-4949",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.fluentd.org/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-732"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The td-agent-builder plugin before 2020-12-18 for Fluentd allows attackers to gain privileges because the bin directory is writable by a user account, but a file in bin is executed as NT AUTHORITY\\SYSTEM."
    },
    {
      "lang": "es",
      "value": "El plugin td-agent-builder antes del 18-12-2020 para Fluentd permite a atacantes alcanzar privilegios porque el directorio bin es escribible por una cuenta de usuario, pero un archivo en bin es ejecutado como NT AUTHORITY\\SYSTEM"
    }
  ],
  "lastModified": "2026-06-17T03:10:09.877",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:td-agent-builder_project:td-agent-builder:*:*:*:*:*:fluentd:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C502E5D4-3955-4C31-97EB-602E13683A50",
              "versionEndExcluding": "2020-12-18"
            }
          ],
          "operator": "OR"
        },
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*",
              "vulnerable": false,
              "matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA"
            }
          ],
          "operator": "OR"
        }
      ],
      "operator": "AND"
    },
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}