ubuntu-cve-2019-12521
Vulnerability from osv_ubuntu
Published
2020-04-15 19:15
Modified
2025-09-08 16:45
Summary
Details

An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.

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

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "squid",
            "binary_version": "3.5.12-1ubuntu7.11"
          },
          {
            "binary_name": "squid-cgi",
            "binary_version": "3.5.12-1ubuntu7.11"
          },
          {
            "binary_name": "squid-common",
            "binary_version": "3.5.12-1ubuntu7.11"
          },
          {
            "binary_name": "squid-purge",
            "binary_version": "3.5.12-1ubuntu7.11"
          },
          {
            "binary_name": "squid3",
            "binary_version": "3.5.12-1ubuntu7.11"
          },
          {
            "binary_name": "squidclient",
            "binary_version": "3.5.12-1ubuntu7.11"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "squid3",
        "purl": "pkg:deb/ubuntu/squid3@3.5.12-1ubuntu7.11?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.12-1ubuntu7.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.3.8-1ubuntu16",
        "3.3.8-1ubuntu17",
        "3.5.12-1ubuntu6",
        "3.5.12-1ubuntu7",
        "3.5.12-1ubuntu7.1",
        "3.5.12-1ubuntu7.2",
        "3.5.12-1ubuntu7.3",
        "3.5.12-1ubuntu7.4",
        "3.5.12-1ubuntu7.5",
        "3.5.12-1ubuntu7.6",
        "3.5.12-1ubuntu7.7",
        "3.5.12-1ubuntu7.8",
        "3.5.12-1ubuntu7.9",
        "3.5.12-1ubuntu7.10"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "squid",
            "binary_version": "3.5.27-1ubuntu1.6"
          },
          {
            "binary_name": "squid-cgi",
            "binary_version": "3.5.27-1ubuntu1.6"
          },
          {
            "binary_name": "squid-common",
            "binary_version": "3.5.27-1ubuntu1.6"
          },
          {
            "binary_name": "squid-purge",
            "binary_version": "3.5.27-1ubuntu1.6"
          },
          {
            "binary_name": "squid3",
            "binary_version": "3.5.27-1ubuntu1.6"
          },
          {
            "binary_name": "squidclient",
            "binary_version": "3.5.27-1ubuntu1.6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "squid3",
        "purl": "pkg:deb/ubuntu/squid3@3.5.27-1ubuntu1.6?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.27-1ubuntu1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5.23-5ubuntu1",
        "3.5.23-5ubuntu2",
        "3.5.27-1ubuntu1",
        "3.5.27-1ubuntu1.1",
        "3.5.27-1ubuntu1.2",
        "3.5.27-1ubuntu1.3",
        "3.5.27-1ubuntu1.4",
        "3.5.27-1ubuntu1.5"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "squid",
            "binary_version": "4.10-1ubuntu1.1"
          },
          {
            "binary_name": "squid-cgi",
            "binary_version": "4.10-1ubuntu1.1"
          },
          {
            "binary_name": "squid-common",
            "binary_version": "4.10-1ubuntu1.1"
          },
          {
            "binary_name": "squid-purge",
            "binary_version": "4.10-1ubuntu1.1"
          },
          {
            "binary_name": "squidclient",
            "binary_version": "4.10-1ubuntu1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "squid",
        "purl": "pkg:deb/ubuntu/squid@4.10-1ubuntu1.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.10-1ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.8-1ubuntu2",
        "4.8-1ubuntu3",
        "4.9-2ubuntu1",
        "4.9-2ubuntu2",
        "4.9-2ubuntu3",
        "4.9-2ubuntu4",
        "4.10-1ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "details": "An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it\u0027s off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can\u0027t affect adjacent memory blocks, and thus just leads to a crash while processing.",
  "id": "UBUNTU-CVE-2019-12521",
  "modified": "2025-09-08T16:45:26Z",
  "published": "2020-04-15T19:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2019-12521"
    },
    {
      "type": "REPORT",
      "url": "https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12521.txt"
    },
    {
      "type": "REPORT",
      "url": "http://www.squid-cache.org/Advisories/SQUID-2019_12.txt"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4356-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2019-12521"
    }
  ],
  "related": [
    "USN-4356-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2019-12521"
  ]
}



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