Vulnerability · Published Oct 5, 2026 · Assigned by Zabbix
CVE-2026-59786Active agent heartbeat missing TLS check
Medium 6.9
In plain English
A medium-severity security flaw in Zabbix from Zabbix. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)6.9Medium
Exploit odds (30 days)0.2%top 89.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Zabbix Server and Proxy accept the active agent heartbeat message regardless of the configured PSK or certificate authentication. This means someone with access to the Zabbix trapper port can report an arbitrary host using an active agent as available, resulting in a loss of integrity.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | zabbix | no fix listed | DEBIAN-CVE-2026-59786 |
| Debian:13 | zabbix | no fix listed | DEBIAN-CVE-2026-59786 |
| Debian:14 | zabbix | 1:7.0.29+dfsg-1 | DEBIAN-CVE-2026-59786 |
| Ubuntu:26.04:LTS | zabbix | no fix listed | UBUNTU-CVE-2026-59786 |
| Ubuntu:26.10 | zabbix | no fix listed | UBUNTU-CVE-2026-59786 |
Affected products (as reported)
Weakness: CWE-940 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N