zabbix — security advisory
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
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"
}