WordPress Stripe Connect Payment Intent ID Validation Flaw

The LatePoint – Calendar Booking Plugin for Appointments and Events plugin for WordPress is vulnerable to Improper Input Validation in all versions up to, and including, 5.4.0. This is due to the plugin's Stripe Connect payment processor accepting a client-supplied PaymentIntent ID. This makes it possible for unauthenticated attackers to pay an arbitrary amount by supplying a previously succeeded PaymentIntent token.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The LatePoint WordPress booking plugin fails to properly validate PaymentIntent IDs submitted to its Stripe Connect payment processor, allowing unauthenticated attackers to exploit previously successful payment tokens to charge arbitrary amounts. This vulnerability affects all versions up to 5.4.0 and impacts any WordPress site running the plugin that accepts payments through Stripe—typically appointment scheduling and event booking platforms serving small businesses, consultants, and service providers. The attack requires no authentication, making it particularly dangerous as threat actors can systematically test known PaymentIntent tokens to process unauthorized transactions.

Casky's 283 matched skills leverage Claude AI's reasoning to detect the attack patterns underlying this vulnerability across MITRE ATT&CK's TA0004 (Privilege Escalation) and TA0006 (Credential Access) techniques. Practitioners using Casky would identify suspicious indicators including: repeated Stripe API calls with reused PaymentIntent tokens, transaction requests originating from unexpected geographic locations or IP addresses, mismatches between user-submitted payment amounts and actual transaction values, and abnormal patterns in the Stripe webhook logs showing successful charges without corresponding legitimate booking requests. The platform's extended reasoning capabilities would correlate these signals—weak input validation on client-supplied identifiers combined with insufficient payment verification—to surface the root cause and recommend implementing server-side PaymentIntent validation and idempotency checks before processing any Stripe transactions.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-5356.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-5356

Casky has 283 skills that investigate the attack patterns behind CVE-2026-5356. Run one and get CVSS-scored findings in 3 minutes.

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