# CVE-2026-9189: Business logic in Contact Form 7 – PayPal & Stripe Add-on

> Unauthenticated attackers can bypass payment verification to mark high-value orders as paid, resulting in unauthorized purchases.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:** 29 May 2026
- **Updated:** 29 May 2026
- **Also known as:** GHSA-vr4h-g9wj-2p4g

## What is CVE-2026-9189?

CVE-2026-9189 is a medium-severity vulnerability in scottpaterson Contact Form 7 – PayPal & Stripe Add-on, published on 29 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Contact Form 7 – PayPal & Stripe Add-on plugin for WordPress is vulnerable to Payment Bypass via Insufficient Verification of Data Authenticity in all versions up to, and including, 2.4.9. Although `cf7pp_paypal_ipn_handler()` correctly validates IPN authenticity by posting back to PayPal with `cmd=_notify-validate`, it fails to compare the IPN payload's `mc_gross` (payment amount), `mc_currency`, or `receiver_email` fields against the corresponding stored order values before passing the attacker-controlled `invoice` field directly to `cf7pp_complete_payment()`, which marks the order completed after only an integer cast with no amount verification. This makes it possible for unauthenticated attackers to mark arbitrary high-value pending orders as fully paid by making a minimal real PayPal payment and crafting an IPN whose `invoice` parameter references the targeted order, effectively completing purchases without tendering the required payment amount.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-9189?


## How do I fix CVE-2026-9189?

No fix has been published for CVE-2026-9189 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9189 being exploited?

There is no known exploitation of CVE-2026-9189 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9189 and fix it if it is affected.

What it is: CVE-2026-9189 is a medium-severity vulnerability in scottpaterson Contact Form 7 – PayPal & Stripe Add-on, published on 29 May 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-2026-9189 in the wild and no public exploit code.

Affected product: scottpaterson Contact Form 7 – PayPal & Stripe Add-on. 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-2026-9189/ (Markdown: https://insights.sbomify.com/CVE-2026-9189/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9189
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9189
- OSV: https://osv.dev/vulnerability/CVE-2026-9189

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9189/
Summaries are generated and may contain mistakes; the official description above is the record.