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zabbix — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-27927

In Zabbix from 4.0.x before 4.0.28rc1, 5.0.0alpha1 before 5.0.10rc1, 5.2.x before 5.2.6rc1, and 5.4.0alpha1 before 5.4.0beta2, the CControllerAuthenticationUpdate controller lacks a CSRF protection mechanism. The code inside this controller calls diableSIDValidation inside the init() method. An attacker doesn't have to know Zabbix user login credentials, but has to know the correct Zabbix URL and contact information of an existing user with sufficient privileges.

Products
zabbix
Affected versions
Not specified
Fixed versions
1:5.0.8+dfsg-1
CVEs
CVE-2021-27927
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 00:05 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-27927

core-osv · Original source

Published 3 Mar 2021, 17:15 UTC

In Zabbix from 4.0.x before 4.0.28rc1, 5.0.0alpha1 before 5.0.10rc1, 5.2.x before 5.2.6rc1, and 5.4.0alpha1 before 5.4.0beta2, the CControllerAuthenticationUpdate controller lacks a CSRF protection mechanism. The code inside this controller calls diableSIDValidation inside the init() method. An attacker doesn't have to know Zabbix user login credentials, but has to know the correct Zabbix URL and contact information of an existing user with sufficient privileges.

osv:DEBIAN-CVE-2021-27927

zabbix

Fixed versions: 1:5.0.8+dfsg-1

zabbix

Fixed versions: 1:5.0.8+dfsg-1

zabbix

Fixed versions: 1:5.0.8+dfsg-1

Complete source record
{
  "id": "8a4653b10c9aa70aaacb9655b590588d5467aedf3469ec9c582f27ff7921166e",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-27927",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-27927",
    "summary": "In Zabbix from 4.0.x before 4.0.28rc1, 5.0.0alpha1 before 5.0.10rc1, 5.2.x before 5.2.6rc1, and 5.4.0alpha1 before 5.4.0beta2, the CControllerAuthenticationUpdate controller lacks a CSRF protection mechanism. The code inside this controller calls diableSIDValidation inside the init() method. An attacker doesn't have to know Zabbix user login credentials, but has to know the correct Zabbix URL and contact information of an existing user with sufficient privileges.",
    "evidence": "osv:DEBIAN-CVE-2021-27927",
    "products": [
      {
        "name": {
          "value": "zabbix",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:5.0.8+dfsg-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "zabbix",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:5.0.8+dfsg-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "zabbix",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1:5.0.8+dfsg-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-27927",
      "aliases": [
        "DEBIAN-CVE-2021-27927"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:5.0.8+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "zabbix",
            "purl": "pkg:deb/debian/zabbix?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-27927.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:5.0.8+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "zabbix",
            "purl": "pkg:deb/debian/zabbix?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-27927.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1:5.0.8+dfsg-1"
                }
              ]
            }
          ],
          "package": {
            "name": "zabbix",
            "purl": "pkg:deb/debian/zabbix?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-27927.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:02:57.637441217Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-27927"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-27927"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-27927",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 419921,
  "published_at": "2021-03-03T17:15:12.753+00:00"
}