« Back to list

CVE-2021-42386

Status: ModifiedHigh (7.2)—

A use-after-free in Busybox's awk applet leads to denial of service and possibly code execution when processing a crafted awk pattern in the nvalloc function

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 (2)

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-42386",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-42386",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-04-23T13:31:59.347231Z"
        }
      }
    ],
    "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": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.2,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.2
      },
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.2,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.2
      }
    ]
  },
  "affected": [
    {
      "source": "reefs@jfrog.com",
      "affectedData": [
        {
          "vendor": "busybox",
          "product": "busybox",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "1.34.0",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-11-15T21:15:08.173",
  "references": [
    {
      "url": "https://claroty.com/team82/research/unboxing-busybox-14-vulnerabilities-uncovered-by-claroty-jfrog",
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://jfrog.com/blog/unboxing-busybox-14-new-vulnerabilities-uncovered-by-claroty-and-jfrog/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6T2TURBYYJGBMQTTN2DSOAIQGP7WCPGV/",
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQXGOGWBIYWOIVXJVRKHZR34UMEHQBXS/",
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://security.netapp.com/advisory/ntap-20211223-0002/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://claroty.com/team82/research/unboxing-busybox-14-vulnerabilities-uncovered-by-claroty-jfrog",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://jfrog.com/blog/unboxing-busybox-14-new-vulnerabilities-uncovered-by-claroty-and-jfrog/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00012.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6T2TURBYYJGBMQTTN2DSOAIQGP7WCPGV/",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQXGOGWBIYWOIVXJVRKHZR34UMEHQBXS/",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://security.netapp.com/advisory/ntap-20211223-0002/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "reefs@jfrog.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A use-after-free in Busybox's awk applet leads to denial of service and possibly code execution when processing a crafted awk pattern in the nvalloc function"
    },
    {
      "lang": "es",
      "value": "Un uso de memoria previamente liberada en el applet awk de Busybox conlleva una denegación de servicio y posiblemente una ejecución de código cuando es procesado un patrón awk diseñado en la función nvalloc"
    }
  ],
  "lastModified": "2026-06-17T04:09:44.730",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:busybox:busybox:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6A24DBA4-B67F-4947-8FF0-8C88257814EE",
              "versionEndIncluding": "1.33.1",
              "versionStartIncluding": "1.16.0"
            }
          ],
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E460AA51-FCDA-46B9-AE97-E6676AA5E194"
            },
            {
              "criteria": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A930E247-0B43-43CB-98FF-6CE7B8189835"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "reefs@jfrog.com"
}