# CVE-2026-100159: Popup Box 6.4.1 - 6.4.2 - Unauthenticated Arbitrary Shortcode Execution via Client-IP / X-Forwarded-For HTTP Headers

> Unauthenticated attackers can execute arbitrary shortcodes via HTTP headers if an admin uses a specific token in popup content, potentially reading data or executing code.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** GHSA-5jv4-j9f2-3247

## What is CVE-2026-100159?

CVE-2026-100159 is a medium-severity code injection vulnerability in ays-pro Popup Box – Create Countdown, Coupon, Video, Contact Form Popups, published on 16 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Popup Box plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions 6.4.1 to 6.4.2. This is due to the ays_popup_get_user_ip() function reading the client-controlled Client-IP / X-Forwarded-For / Forwarded / X-Forwarded / Forwarded-For request headers, sanitizing them only with sanitize_text_field() (which does not strip the bracket, quote, space, or '=' characters used by shortcode syntax), substituting the value into a popup body wherever the %%user_ip_address%% token appears (a raw str_replace with no escaping in Ays_Pb_Data::replace_message_variables()), and then passing the resulting body to do_shortcode() in Ays_Pb_Public::ays_autoembed() at output on the wp_footer hook. This makes it possible for unauthenticated attackers to execute arbitrary registered shortcodes with attacker-supplied attributes on the server whenever an administrator has added the %%user_ip_address%% token to a popup's Custom Content body, which can be leveraged to read arbitrary data or perform other actions exposed by shortcodes installed on the site.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-100159?


## How do I fix CVE-2026-100159?

No fix has been published for CVE-2026-100159 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-100159 being exploited?

There is no known exploitation of CVE-2026-100159 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100159 and fix it if it is affected.

What it is: CVE-2026-100159 is a medium-severity code injection vulnerability in ays-pro Popup Box – Create Countdown, Coupon, Video, Contact Form Popups, published on 16 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-100159 in the wild and no public exploit code.

Affected product: ays-pro Popup Box – Create Countdown, Coupon, Video, Contact Form Popups. 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-2026-100159/ (Markdown: https://insights.sbomify.com/CVE-2026-100159/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100159
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100159
- OSV: https://osv.dev/vulnerability/CVE-2026-100159

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-100159/
Summaries are generated and may contain mistakes; the official description above is the record.