ubuntu-cve-2021-42375
Vulnerability from osv_ubuntu
Published
2021-11-15 21:15
Modified
2025-07-16 04:57
Summary
Details

An incorrect handling of a special element in Busybox's ash applet leads to denial of service when processing a crafted shell command, due to the shell mistaking specific characters for reserved characters. This may be used for DoS under rare conditions of filtered command input.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
negligible
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "busybox",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-dbgsym",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-initramfs",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-initramfs-dbgsym",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-static",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-static-dbgsym",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-syslogd",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "busybox-udeb",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "udhcpc",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          },
          {
            "binary_name": "udhcpd",
            "binary_version": "1:1.27.2-2ubuntu3.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "busybox",
        "purl": "pkg:deb/ubuntu/busybox@1:1.27.2-2ubuntu3.3?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.27.2-2ubuntu3.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.22.0-19ubuntu2",
        "1:1.27.2-1ubuntu3",
        "1:1.27.2-1ubuntu4",
        "1:1.27.2-2ubuntu2",
        "1:1.27.2-2ubuntu3",
        "1:1.27.2-2ubuntu3.1",
        "1:1.27.2-2ubuntu3.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "busybox",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-dbgsym",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-initramfs",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-initramfs-dbgsym",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-static",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-static-dbgsym",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-syslogd",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "busybox-udeb",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "udhcpc",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          },
          {
            "binary_name": "udhcpd",
            "binary_version": "1:1.30.1-4ubuntu6.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "busybox",
        "purl": "pkg:deb/ubuntu/busybox@1:1.30.1-4ubuntu6.3?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.30.1-4ubuntu6.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:1.30.1-4ubuntu4",
        "1:1.30.1-4ubuntu5",
        "1:1.30.1-4ubuntu6",
        "1:1.30.1-4ubuntu6.1",
        "1:1.30.1-4ubuntu6.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "busybox",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "busybox-dbgsym",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "busybox-initramfs",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "busybox-initramfs-dbgsym",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "busybox-static",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "busybox-static-dbgsym",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "busybox-syslogd",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "udhcpc",
            "binary_version": "1:1.30.1-6ubuntu3"
          },
          {
            "binary_name": "udhcpd",
            "binary_version": "1:1.30.1-6ubuntu3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "busybox",
        "purl": "pkg:deb/ubuntu/busybox@1:1.30.1-6ubuntu3?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:1.30.1-6ubuntu3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [],
  "details": "An incorrect handling of a special element in Busybox\u0027s ash applet leads to denial of service when processing a crafted shell command, due to the shell mistaking specific characters for reserved characters. This may be used for DoS under rare conditions of filtered command input.",
  "id": "UBUNTU-CVE-2021-42375",
  "modified": "2025-07-16T04:57:36Z",
  "published": "2021-11-15T21:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-42375"
    },
    {
      "type": "REPORT",
      "url": "https://jfrog.com/blog/unboxing-busybox-14-new-vulnerabilities-uncovered-by-claroty-and-jfrog/"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-42375"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "negligible",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-42375"
  ],
  "withdrawn": "2025-07-18T16:47:01Z"
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.