CVE-2020-12255

Status: ModifiedHigh (8.8)—PoC

Severity8.8High · CVSS 3.1

Exploitation probability58 %higher than 99% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitAvailableProof of concept on GitHub (unverified)

rConfig 3.9.4 is vulnerable to remote code execution due to improper validation in the file upload functionality. vendor.crud.php accepts a file upload by checking content-type without considering the file extension and header. Thus, an attacker can exploit this by uploading a .php file to vendor.php that contains arbitrary PHP code and changing the content-type to image/gif.

CVSS

Base score: 8.8
Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 58 %
Percentile among all scored CVEs: 99
Score date: 10/28/2026

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.

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 (1)

Rconfig — Rconfig

CWEs

CWE-434

References

Show 2 references

Raw JSON (NVD)

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{
  "id": "CVE-2020-12255",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 6.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:P/I:P/A:P",
          "authentication": "SINGLE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-05-18T15:15:10.880",
  "references": [
    {
      "url": "https://gist.github.com/farid007/9f6ad063645d5b1550298c8b9ae953ff",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://gist.github.com/farid007/9f6ad063645d5b1550298c8b9ae953ff",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-434"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "rConfig 3.9.4 is vulnerable to remote code execution due to improper validation in the file upload functionality. vendor.crud.php accepts a file upload by checking content-type without considering the file extension and header. Thus, an attacker can exploit this by uploading a .php file to vendor.php that contains arbitrary PHP code and changing the content-type to image/gif."
    },
    {
      "lang": "es",
      "value": "rConfig versión 3.9.4, es vulnerable a una ejecución de código remota debido a una comprobación inapropiada en la funcionalidad file upload. El archivo vendor.crud.php acepta la carga de un archivo al comprobar el content-type sin considerar la extensión y el encabezado del archivo. Por lo tanto, un atacante puede explotar esto al cargar un archivo .php en el archivo vendor.php que contiene código PHP arbitrario y cambia el content-type a image/gif."
    }
  ],
  "lastModified": "2026-06-17T02:51:31.160",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:rconfig:rconfig:3.9.4:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0B529174-50B3-491D-BEA0-5A0EC8BF45B6"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}