CVE-2026-59786 PUBLISHED

Active agent heartbeat missing TLS check

Assigner: Zabbix
Reserved: 07.07.2026 Published: 05.10.2026 Updated: 05.10.2026

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.

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 6.9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Zabbix
Product	Zabbix
Versions	Default: unknown affected from 7.0.0 to 7.0.28 (incl.) affected from 7.4.0 to 7.4.12 (incl.)

Affected Configurations

Attacker with network access to the trapper port sending crafted heartbeat packets.

Solutions

Update the affected components to their respective fixed versions.

Credits

Zabbix wants to thank Aditya Bisht for submitting this report on the HackerOne bug bounty platform. reporter

References

https://support.zabbix.com/browse/ZBX-28196

Problem Types

CWE-940: Improper Verification of Source of a Communication Channel CWE

Impacts

CAPEC-194: Fake the Source of Data