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e2guardian — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-44273

e2guardian v5.4.x <= v5.4.3r is affected by missing SSL certificate validation in the SSL MITM engine. In standalone mode (i.e., acting as a proxy or a transparent proxy), with SSL MITM enabled, e2guardian, if built with OpenSSL v1.1.x, did not validate hostnames in certificates of the web servers that it connected to, and thus was itself vulnerable to MITM attacks.

Products
e2guardian
Affected versions
Not specified
Fixed versions
5.3.5-3
CVEs
CVE-2021-44273
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 01:09 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-44273

core-osv · Original source

Published 23 Dec 2021, 12:15 UTC

e2guardian v5.4.x <= v5.4.3r is affected by missing SSL certificate validation in the SSL MITM engine. In standalone mode (i.e., acting as a proxy or a transparent proxy), with SSL MITM enabled, e2guardian, if built with OpenSSL v1.1.x, did not validate hostnames in certificates of the web servers that it connected to, and thus was itself vulnerable to MITM attacks.

osv:DEBIAN-CVE-2021-44273

e2guardian

Fixed versions: 5.3.5-3

e2guardian

Fixed versions: 5.3.5-3

e2guardian

Fixed versions: 5.3.5-3

Complete source record
{
  "id": "79e283483ae52e0d10468ccc4fa3c02da130653bb4e4dbf4417c95b79483de75",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-44273",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-44273",
    "summary": "e2guardian v5.4.x <= v5.4.3r is affected by missing SSL certificate validation in the SSL MITM engine. In standalone mode (i.e., acting as a proxy or a transparent proxy), with SSL MITM enabled, e2guardian, if built with OpenSSL v1.1.x, did not validate hostnames in certificates of the web servers that it connected to, and thus was itself vulnerable to MITM attacks.",
    "evidence": "osv:DEBIAN-CVE-2021-44273",
    "products": [
      {
        "name": {
          "value": "e2guardian",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.3.5-3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "e2guardian",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.3.5-3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "e2guardian",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.3.5-3",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-44273",
      "aliases": [
        "DEBIAN-CVE-2021-44273"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.3.5-3"
                }
              ]
            }
          ],
          "package": {
            "name": "e2guardian",
            "purl": "pkg:deb/debian/e2guardian?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-44273.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.3.5-3"
                }
              ]
            }
          ],
          "package": {
            "name": "e2guardian",
            "purl": "pkg:deb/debian/e2guardian?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-44273.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.3.5-3"
                }
              ]
            }
          ],
          "package": {
            "name": "e2guardian",
            "purl": "pkg:deb/debian/e2guardian?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-44273.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:04:17.155696041Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-44273"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-44273"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-44273",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 423159,
  "published_at": "2021-12-23T12:15:07.387+00:00"
}