FKIE_CVE-2026-71268

Vulnerability from fkie_nvd - Published: 2026-08-05 13:24 - Updated: 2026-08-05 16:17
Severity
9.9 (Critical) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
OpenPLC Runtime v3's compile_program() function (webserver/openplc.py) parses `(*FILE:path content*)` directives from uploaded Structured Text (.st) program files and writes the referenced content to `os.path.join('./core', file_path)` with no validation that file_path stays within the ./core directory. A crafted .st file containing a directive such as `(*FILE:../../../etc/cron.d/x * * * * root <command>*)` writes attacker-controlled content to an arbitrary filesystem path, enabling remote code execution (e.g. via cron or SSH authorized_keys). A path-validation function, validate_file_path(), exists elsewhere in the codebase (webserver/credentials.py) but is never invoked from compile_program(), leaving the sink unprotected. OpenPLC additionally ships with hardcoded default credentials (openplc:openplc), lowering the practical bar for exploitation.
References
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2chttps://github.com/thiagoralves/OpenPLC_v3
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2chttps://github.com/thiagoralves/OpenPLC_v3/blob/master/webserver/openplc.py
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "OpenPLC_v3",
          "programFiles": [
            "webserver/openplc.py"
          ],
          "vendor": "thiagoralves",
          "versions": [
            {
              "lessThanOrEqual": "*",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "OpenPLC Runtime v3\u0027s compile_program() function (webserver/openplc.py) parses `(*FILE:path content*)` directives from uploaded Structured Text (.st) program files and writes the referenced content to `os.path.join(\u0027./core\u0027, file_path)` with no validation that file_path stays within the ./core directory. A crafted .st file containing a directive such as `(*FILE:../../../etc/cron.d/x * * * * root \u003ccommand\u003e*)` writes attacker-controlled content to an arbitrary filesystem path, enabling remote code execution (e.g. via cron or SSH authorized_keys). A path-validation function, validate_file_path(), exists elsewhere in the codebase (webserver/credentials.py) but is never invoked from compile_program(), leaving the sink unprotected. OpenPLC additionally ships with hardcoded default credentials (openplc:openplc), lowering the practical bar for exploitation."
    }
  ],
  "id": "CVE-2026-71268",
  "lastModified": "2026-08-05T16:17:06.173",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.9,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 6.0,
        "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-71268",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-05T15:41:39.300095Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-05T13:24:51.083",
  "references": [
    {
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "url": "https://github.com/thiagoralves/OpenPLC_v3"
    },
    {
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "url": "https://github.com/thiagoralves/OpenPLC_v3/blob/master/webserver/openplc.py"
    }
  ],
  "sourceIdentifier": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ],
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "type": "Secondary"
    }
  ]
}



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