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CVE-2020-23622

Status: ModifiedHigh (7.5)—
Severity7.5High · CVSS 3.1
Exploitation probability1.12 %higher than 66% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

An issue in the UPnP protocol in 4thline cling 2.0.0 through 2.1.2 allows remote attackers to cause a denial of service via an unchecked CALLBACK parameter in the request header

CVSS

Base score
7.5
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
1.12 %
Percentile among all scored CVEs
66
Score date
10/24/2026

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).

Affected technologies (1)

Cling Project — Cling

CWEs

References

Show 4 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2020-23622",
  "cveTags": [
    {
      "tags": [
        "unsupported-when-assigned"
      ],
      "sourceIdentifier": "cve@mitre.org"
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2022-08-15T20:15:09.040",
  "references": [
    {
      "url": "https://github.com/4thline/cling/issues/253",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://zh-cn.tenable.com/blog/cve-2020-12695-callstranger-vulnerability-in-universal-plug-and-play-upnp-puts-billions-of?tns_redirect=true",
      "tags": [
        "Not Applicable"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/4thline/cling/issues/253",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://zh-cn.tenable.com/blog/cve-2020-12695-callstranger-vulnerability-in-universal-plug-and-play-upnp-puts-billions-of?tns_redirect=true",
      "tags": [
        "Not Applicable"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue in the UPnP protocol in 4thline cling 2.0.0 through 2.1.2 allows remote attackers to cause a denial of service via an unchecked CALLBACK parameter in the request header"
    },
    {
      "lang": "es",
      "value": "** NO SOPORTADO CUANDO SE ASIGNÓ ** Un problema en el protocolo UPnP en 4thline cling versiones 2.0.0 hasta 2.1.2, permite a atacantes remotos causar una denegación de servicio por medio de un parámetro CALLBACK no comprobado en el encabezado de la petición."
    }
  ],
  "lastModified": "2026-06-17T03:04:52.650",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:cling_project:cling:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "740B8998-CC1B-4AC7-A0EC-216E4230D80F",
              "versionEndIncluding": "2.1.2",
              "versionStartIncluding": "2.0.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}