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CVE-2020-13111

Status: ModifiedHigh (7.5)—

NaviServer 4.99.4 to 4.99.19 allows denial of service due to the nsd/driver.c ChunkedDecode function not properly validating the length of a chunk. A remote attacker can craft a chunked-transfer request that will result in a negative value being passed to memmove via the size parameter, causing the process to crash.

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)

Naviserver Project — Naviserver

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2020-13111",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "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": "2020-05-16T15:15:11.377",
  "references": [
    {
      "url": "https://bitbucket.org/naviserver/naviserver/commits/a5c3079f1d8996d5f34c9384a440acf3519ca3bb",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://sourceforge.net/p/naviserver/bugs/89/",
      "tags": [
        "Permissions Required",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://bitbucket.org/naviserver/naviserver/commits/a5c3079f1d8996d5f34c9384a440acf3519ca3bb",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://sourceforge.net/p/naviserver/bugs/89/",
      "tags": [
        "Permissions Required",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "NaviServer 4.99.4 to 4.99.19 allows denial of service due to the nsd/driver.c ChunkedDecode function not properly validating the length of a chunk. A remote attacker can craft a chunked-transfer request that will result in a negative value being passed to memmove via the size parameter, causing the process to crash."
    },
    {
      "lang": "es",
      "value": "NaviServer versiones 4.99.4 hasta 4.99.19, permite una denegación de servicio debido a que la función ChunkedDecode del archivo nsd/driver.c, no comprueba apropiadamente la longitud de un fragmento. Un atacante remoto puede diseñar una petición de transferencia fragmentada que resultará en que un valor negativo pasara hacia memmove por medio del parámetro size, causando que el proceso se bloquee."
    }
  ],
  "lastModified": "2026-06-17T02:52:38.447",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:naviserver_project:naviserver:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C6BF22E9-DF07-4368-B238-B7B0E458A222",
              "versionEndIncluding": "4.99.19",
              "versionStartIncluding": "4.99.4"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}