ubuntu-cve-2021-40438
Vulnerability from osv_ubuntu
Published
2021-09-16 15:15
Modified
2026-04-22 07:40
Summary
Details

A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.

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

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "apache2",
            "binary_version": "2.4.18-2ubuntu3.17+esm3"
          },
          {
            "binary_name": "apache2-bin",
            "binary_version": "2.4.18-2ubuntu3.17+esm3"
          },
          {
            "binary_name": "apache2-data",
            "binary_version": "2.4.18-2ubuntu3.17+esm3"
          },
          {
            "binary_name": "apache2-suexec-custom",
            "binary_version": "2.4.18-2ubuntu3.17+esm3"
          },
          {
            "binary_name": "apache2-suexec-pristine",
            "binary_version": "2.4.18-2ubuntu3.17+esm3"
          },
          {
            "binary_name": "apache2-utils",
            "binary_version": "2.4.18-2ubuntu3.17+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "apache2",
        "purl": "pkg:deb/ubuntu/apache2@2.4.18-2ubuntu3.17+esm3?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.18-2ubuntu3.17+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.4.12-2ubuntu2",
        "2.4.17-1ubuntu1",
        "2.4.17-2ubuntu1",
        "2.4.17-3ubuntu1",
        "2.4.18-1ubuntu1",
        "2.4.18-2ubuntu1",
        "2.4.18-2ubuntu2",
        "2.4.18-2ubuntu3",
        "2.4.18-2ubuntu3.1",
        "2.4.18-2ubuntu3.2",
        "2.4.18-2ubuntu3.3",
        "2.4.18-2ubuntu3.4",
        "2.4.18-2ubuntu3.5",
        "2.4.18-2ubuntu3.7",
        "2.4.18-2ubuntu3.8",
        "2.4.18-2ubuntu3.9",
        "2.4.18-2ubuntu3.10",
        "2.4.18-2ubuntu3.12",
        "2.4.18-2ubuntu3.13",
        "2.4.18-2ubuntu3.14",
        "2.4.18-2ubuntu3.15",
        "2.4.18-2ubuntu3.17",
        "2.4.18-2ubuntu3.17+esm1",
        "2.4.18-2ubuntu3.17+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "apache2",
            "binary_version": "2.4.29-1ubuntu4.18"
          },
          {
            "binary_name": "apache2-bin",
            "binary_version": "2.4.29-1ubuntu4.18"
          },
          {
            "binary_name": "apache2-data",
            "binary_version": "2.4.29-1ubuntu4.18"
          },
          {
            "binary_name": "apache2-suexec-custom",
            "binary_version": "2.4.29-1ubuntu4.18"
          },
          {
            "binary_name": "apache2-suexec-pristine",
            "binary_version": "2.4.29-1ubuntu4.18"
          },
          {
            "binary_name": "apache2-utils",
            "binary_version": "2.4.29-1ubuntu4.18"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "apache2",
        "purl": "pkg:deb/ubuntu/apache2@2.4.29-1ubuntu4.18?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.29-1ubuntu4.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.4.27-2ubuntu3",
        "2.4.29-1ubuntu1",
        "2.4.29-1ubuntu2",
        "2.4.29-1ubuntu3",
        "2.4.29-1ubuntu4",
        "2.4.29-1ubuntu4.1",
        "2.4.29-1ubuntu4.2",
        "2.4.29-1ubuntu4.3",
        "2.4.29-1ubuntu4.4",
        "2.4.29-1ubuntu4.5",
        "2.4.29-1ubuntu4.6",
        "2.4.29-1ubuntu4.7",
        "2.4.29-1ubuntu4.8",
        "2.4.29-1ubuntu4.10",
        "2.4.29-1ubuntu4.11",
        "2.4.29-1ubuntu4.12",
        "2.4.29-1ubuntu4.13",
        "2.4.29-1ubuntu4.14",
        "2.4.29-1ubuntu4.16",
        "2.4.29-1ubuntu4.17"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "apache2",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "apache2-bin",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "apache2-data",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "apache2-suexec-custom",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "apache2-suexec-pristine",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "apache2-utils",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "libapache2-mod-md",
            "binary_version": "2.4.41-4ubuntu3.6"
          },
          {
            "binary_name": "libapache2-mod-proxy-uwsgi",
            "binary_version": "2.4.41-4ubuntu3.6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "apache2",
        "purl": "pkg:deb/ubuntu/apache2@2.4.41-4ubuntu3.6?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.41-4ubuntu3.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.4.41-1ubuntu1",
        "2.4.41-4ubuntu1",
        "2.4.41-4ubuntu2",
        "2.4.41-4ubuntu3",
        "2.4.41-4ubuntu3.1",
        "2.4.41-4ubuntu3.3",
        "2.4.41-4ubuntu3.4",
        "2.4.41-4ubuntu3.5"
      ]
    }
  ],
  "aliases": [],
  "details": "A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.",
  "id": "UBUNTU-CVE-2021-40438",
  "modified": "2026-04-22T07:40:09Z",
  "published": "2021-09-16T15:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-40438"
    },
    {
      "type": "REPORT",
      "url": "https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2021-40438"
    },
    {
      "type": "REPORT",
      "url": "https://httpd.apache.org/security/vulnerabilities_24.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5090-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5090-2"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5090-3"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5090-2"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-40438"
    },
    {
      "type": "REPORT",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog"
    }
  ],
  "related": [
    "USN-5090-1",
    "USN-5090-2",
    "USN-5090-3 (regression update)",
    "USN-5090-2 (regression update esm)"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-40438"
  ]
}



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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.
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