# CVE-2026-2428: Fluent Forms Pro Add On Pack <= 6.1.17 - Missing Authorization to Unauthenticated Payment Status modification

> Unauthenticated attackers can forge PayPal IPN notifications to mark unpaid form submissions as paid, triggering post-payment automation and granting unauthorized access.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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:** 27 Feb 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-23j5-87fx-hgc9

## What is CVE-2026-2428?

CVE-2026-2428 is a high-severity missing authorization vulnerability in techjewel Fluent Forms Pro Add On Pack, published on 27 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Fluent Forms Pro Add On Pack plugin for WordPress is vulnerable to Insufficient Verification of Data Authenticity in all versions up to, and including, 6.1.17. This is due to the PayPal IPN (Instant Payment Notification) verification being disabled by default (`disable_ipn_verification` defaults to `'yes'` in `PayPalSettings.php`). This makes it possible for unauthenticated attackers to send forged PayPal IPN notifications to the publicly accessible IPN endpoint, marking unpaid form submissions as "paid" and triggering post-payment automation (emails, access grants, digital product delivery).

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

## Which versions are affected by CVE-2026-2428?


## How do I fix CVE-2026-2428?

No fix has been published for CVE-2026-2428 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2428 being exploited?

There is no known exploitation of CVE-2026-2428 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2428 and fix it if it is affected.

What it is: CVE-2026-2428 is a high-severity missing authorization vulnerability in techjewel Fluent Forms Pro Add On Pack, published on 27 Feb 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-2026-2428 in the wild and no public exploit code.

Affected product: techjewel Fluent Forms Pro Add On Pack. 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-2026-2428/ (Markdown: https://insights.sbomify.com/CVE-2026-2428/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2428
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2428
- OSV: https://osv.dev/vulnerability/CVE-2026-2428

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2428/
Summaries are generated and may contain mistakes; the official description above is the record.