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

> Unauthenticated attackers can inject arbitrary web scripts via the HTTP_REFERER header in the Email Subscription Popup WordPress plugin.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Dec 2023
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-fv9g-wpxr-g2cq

## What is CVE-2023-6527?

CVE-2023-6527 is a medium-severity cross-site scripting vulnerability in nik00726 Email Subscription Popup, published on 6 Dec 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2023-6527?

It affects 1 product.


Products: I13websolution Email Subscription Popup.

## How do I fix CVE-2023-6527?

No fix has been published for CVE-2023-6527 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-6527 being exploited?

There is no known exploitation of CVE-2023-6527 in the wild and no public exploit code.

## Other vulnerabilities in nik00726 Email Subscription Popup

- [CVE-2024-27960](https://insights.sbomify.com/CVE-2024-27960/): WordPress Email Subscription Popup plugin <= 1.2.20 - Cross Site Scripting (XSS) vulnerability (high 7.1)
- [CVE-2023-30489](https://insights.sbomify.com/CVE-2023-30489/): WordPress Email Subscription Popup Plugin <= 1.2.16 is vulnerable to Cross Site Scripting (XSS) (high 7.1)
- [CVE-2024-11195](https://insights.sbomify.com/CVE-2024-11195/): Cross-site scripting in Email Subscription Popup (medium 6.4)
- [CVE-2023-6555](https://insights.sbomify.com/CVE-2023-6555/): Email Subscription Popup < 1.2.20 - Reflected XSS (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-6527 and fix it if it is affected.

What it is: CVE-2023-6527 is a medium-severity cross-site scripting vulnerability in nik00726 Email Subscription Popup, published on 6 Dec 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-6527 in the wild and no public exploit code.

Affected product: nik00726 Email Subscription Popup. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-6527/ (Markdown: https://insights.sbomify.com/CVE-2023-6527/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-6527
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6527
- OSV: https://osv.dev/vulnerability/CVE-2023-6527

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-6527/
Summaries are generated and may contain mistakes; the official description above is the record.