rustaurius Five Star Restaurant Reservations Plugin up to 2.7.16 on WordPress AJAX valid_payment payment_id data authenticity

Summaryinfo

A vulnerability identified as critical has been detected in rustaurius Five Star Restaurant Reservations Plugin up to 2.7.16 on WordPress. The impacted element is the function valid_payment of the component AJAX Handler. The manipulation of the argument payment_id leads to data authenticity. This vulnerability is uniquely identified as CVE-2026-6498. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in rustaurius Five Star Restaurant Reservations Plugin up to 2.7.16 on WordPress and classified as critical. This issue affects the function valid_payment of the component AJAX Handler. The manipulation of the argument payment_id with an unknown input leads to a data authenticity vulnerability. Using CWE to declare the problem leads to CWE-345. The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

The Five Star Restaurant Reservations plugin for WordPress is vulnerable to a payment bypass via PHP type juggling in versions up to, and including, 2.7.16 This is due to the valid_payment() function using a PHP loose comparison (==) between the attacker-controlled payment_id POST parameter and the booking's stripe_payment_intent_id property. When an unauthenticated attacker submits a request to the nopriv AJAX handler rtb_stripe_pmt_succeed before the Stripe payment intent has been created for a booking (i.e., before the JavaScript-triggered create_stripe_pmtIntnt() call has stored an intent ID in post meta), the stripe_payment_intent_id property on the booking object remains null. The comparison sanitize_text_field('') == null evaluates to TRUE in PHP loose comparison, causing the payment verification check to pass with zero actual payment. This makes it possible for unauthenticated attackers to mark any existing payment_pending booking as paid without completing a Stripe payment by submitting an empty payment_id parameter.

The weakness was disclosed by David Fernández Morilla. The advisory is shared at wordfence.com. The identification of this vulnerability is CVE-2026-6498 since 04/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 04/30/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Hospitality Software

Vendor

• rustaurius

Name

• Five Star Restaurant Reservations Plugin

Version

• 2.7.0
• 2.7.1
• 2.7.2
• 2.7.3
• 2.7.4
• 2.7.5
• 2.7.6
• 2.7.7
• 2.7.8
• 2.7.9
• 2.7.10
• 2.7.11
• 2.7.12
• 2.7.13
• 2.7.14
• 2.7.15
• 2.7.16

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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