CVE-2026-78303 in SP Property Extension
Summary
by MITRE • 09/10/2026
Joomla Extension - joomshaper.com - Unvalidated Email Destination & Form Manipulation in Booking Requests in SP Property < 4.1.4 - Booking inquiries previously relied on client-submitted hidden fields for recipient routing, allowing potential email manipulation.
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Analysis
by VulDB Data Team • 09/10/2026
The vulnerability identified within the SP Property extension for Joomla versions prior to 4.1.4 represents a critical flaw in input validation and server-side logic handling related to form processing. Specifically, the component utilized unvalidated client-submitted hidden fields to determine the recipient of booking inquiry emails. In web application architecture, hidden form fields are often used to pass state information or configuration parameters from the frontend interface to the backend processor without displaying them to the end user. However, relying on these values for critical routing decisions such as email delivery destinations introduces a severe security risk because data originating from the client side cannot be trusted by default. An attacker can easily manipulate HTTP requests using tools like Burp Suite or curl to alter the value of these hidden fields before submission, effectively bypassing any intended logic that restricts who receives the inquiry data.
This specific technical flaw falls under the category of Improper Input Validation and is closely aligned with CWE-20: Improper Input Validation as well as CWE-613: Insufficient Session Expiration or CWE-related concepts regarding insecure direct object references if the routing leads to sensitive internal resources. More specifically, this behavior exemplifies CWE-915: Improper Control of Dynamically-Identified Variables, where a variable is controlled by an external source without proper validation against a whitelist of acceptable values. The operational impact of this vulnerability allows for Email Header Injection and BCC Blind Carbon Copy injection attacks. By manipulating the recipient field or injecting additional headers through newline characters in the form data, an attacker can redirect sensitive booking inquiries to unintended recipients, potentially exposing personal identifiable information such as names, contact details, and property preferences to malicious actors or competitors. Furthermore, this manipulation could facilitate phishing campaigns where attackers use the compromised Joomla site's domain reputation to send fraudulent emails that appear legitimate to victims.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK technique T1534: Internal Spearphishing if used for internal data exfiltration or lateral movement within an organization using the joomshaper infrastructure as a relay point. It also relates to T1078: Valid Accounts if the attacker leverages valid user credentials to submit manipulated forms, although in this case, anonymous users may often be able to exploit it depending on Joomla's global configuration for public form access. The exploitation does not require authentication in many default configurations of such extensions, making it a high-severity issue accessible to unauthenticated attackers across the internet.
Mitigation strategies must focus on strict server-side validation and avoiding reliance on client-supplied data for security-critical operations. Developers should implement a whitelist approach where only predefined, hardcoded email addresses or user IDs are accepted as valid recipients for booking inquiries. Any input received from form submissions that attempts to specify routing logic should be ignored in favor of server-determined values based on the authenticated session context or static configuration settings. Additionally, implementing Content Security Policy headers and validating all incoming data against expected formats can reduce the attack surface. For administrators running affected versions, immediate upgrading to SP Property version 4.1.4 or later is required as this release addresses the unvalidated email destination issue by enforcing proper validation protocols on form submissions. Until an update is applied, restricting public access to booking forms via IP whitelisting or CAPTCHA mechanisms can provide a temporary layer of defense against automated exploitation attempts.