# CVE-2026-4001: Woocommerce Custom Product Addons Pro <= 5.4.1 - Unauthenticated Remote Code Execution via Custom Pricing Formula

> Unauthenticated attackers can execute arbitrary code on servers using the WooCommerce Custom Product Addons Pro plugin by injecting PHP code into custom pricing formulas.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Mar 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-2qpc-rpxq-phv6

## What is CVE-2026-4001?

CVE-2026-4001 is a critical code injection vulnerability in acowebs Woocommerce Custom Product Addons Pro, published on 23 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Woocommerce Custom Product Addons Pro plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 5.4.1 via the custom pricing formula eval() in the process_custom_formula() function within includes/process/price.php. This is due to insufficient sanitization and validation of user-submitted field values before passing them to PHP's eval() function. The sanitize_values() method strips HTML tags but does not escape single quotes or prevent PHP code injection. This makes it possible for unauthenticated attackers to execute arbitrary code on the server by submitting a crafted value to a WCPA text field configured with custom pricing formula (pricingType: "custom" with {this.value}).

Weakness: CWE-95 (Improper Neutralization of Directives in Dynamically Evaluated Code)

## Which versions are affected by CVE-2026-4001?


## How do I fix CVE-2026-4001?

No fix has been published for CVE-2026-4001 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4001 being exploited?

There is no known exploitation of CVE-2026-4001 in the wild and no public exploit code.

Public exploit code:

- WooCommerce plugin: safe formula-based product pricing, closing CVE-2026-4001's eval()-based RCE (github_poc): https://github.com/htrxuan/hdwebmobile-formula-pricing

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4001 and fix it if it is affected.

What it is: CVE-2026-4001 is a critical code injection vulnerability in acowebs Woocommerce Custom Product Addons Pro, published on 23 Mar 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-2026-4001 in the wild and no public exploit code.

Affected product: acowebs Woocommerce Custom Product Addons Pro. 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-2026-4001/ (Markdown: https://insights.sbomify.com/CVE-2026-4001/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4001
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4001
- OSV: https://osv.dev/vulnerability/CVE-2026-4001

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-4001/
Summaries are generated and may contain mistakes; the official description above is the record.