# CVE-2026-4987: SureForms <= 2.5.2 - Unauthenticated Payment Amount Validation Bypass via 'form_id'

- Exploited (CISA KEV): no
- Published: 2026-03-28
- CVSS: 7.5 HIGH (v3.1)
- EPSS: 1.0% (61th percentile)
- CWE: CWE-20

The SureForms – Contact Form, Payment Form & Other Custom Form Builder plugin for WordPress is vulnerable to Payment Amount Bypass in all versions up to, and including, 2.5.2. This is due to the create_payment_intent() function performing a payment validation solely based on the value of a user-controlled parameter. This makes it possible for unauthenticated attackers to bypass configured form payment-amount validation and create underpriced payment/subscription intents by setting form_id to 0.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | No public claim | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2026-10-21 | 207 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### F5

- 2026-10-21 · new · rule 200013225
  > Added: signature 200013225 "WordPress SureForms Payment Bypass" (Authentication/Authorization Attacks, risk Medium), systems: WordPress. References: CVE-2026-4987.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: passed (0 of 3 requests blocked), template CVE-2026-4987, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: passed (0 of 3 requests blocked), template CVE-2026-4987, 2026-11-02

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2026-4987 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-4987