CVE-2024-13784: 
WordPress vulnerability analysis and mitigation

CVE-2024-13784 is a PHP Object Injection vulnerability in the Contact Form, Survey, Quiz & Popup Form Builder – ARForms plugin for WordPress, affecting all versions up to and including 1.8.5. The flaw arises from deserialization of untrusted input submitted via forms, allowing unauthenticated attackers to inject arbitrary PHP objects. It was published on August 16, 2026, and carries a CVSS v3.1 base score of 9.8 (Critical) (GitHub Advisory).

The vulnerability is classified as CWE-502 (Deserialization of Untrusted Data). The ARForms plugin deserializes user-supplied data from form submissions without adequate validation, enabling unauthenticated attackers to inject malicious PHP objects over the network with no user interaction required. Exploitation to achieve meaningful impact depends on the presence of a compatible Property-Oriented Programming (POP) chain in another installed plugin or theme — no POP chain is present in ARForms itself. If a POP chain exists in the environment, it can be leveraged to delete files, exfiltrate sensitive data, or execute arbitrary code (GitHub Advisory, Feedly).

If a compatible POP chain is present via another installed plugin or theme, an unauthenticated remote attacker could achieve full compromise of the WordPress site — including arbitrary code execution, deletion of arbitrary files, and retrieval of sensitive data such as credentials or database contents. Without a POP chain, the vulnerability has no direct impact. The attack is automatable and requires no privileges or user interaction, making it a high-risk exposure in environments with multiple plugins installed (GitHub Advisory, Feedly).

There is no known public proof-of-concept exploit and no evidence of active in-the-wild exploitation at this time (Feedly). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.519%, placing it in the 42nd percentile for exploitation likelihood within 30 days (GitHub Advisory). NVD SSVC assessment notes the attack is automatable with total technical impact potential, but exploitation is currently rated as "none" (Feedly).

1. Reconnaissance: Identify WordPress sites running the ARForms plugin (versions ≤ 1.8.5) using tools like WPScan, Shodan, or by inspecting plugin directories exposed via the target site.
2. Identify POP chain: Enumerate other installed plugins and themes on the target site to determine if any contain known PHP gadget chains (POP chains) compatible with PHP object injection.
3. Craft malicious payload: Construct a serialized PHP object payload targeting a known POP chain present in the environment (e.g., using tools like PHPGGC to generate gadget chain payloads).
4. Submit via form: Submit the crafted serialized payload through an ARForms form submission endpoint, exploiting the lack of input validation during deserialization.
5. Trigger POP chain: The deserialized object triggers the POP chain in the co-installed plugin/theme, resulting in the attacker's chosen action — such as remote code execution, file deletion, or data exfiltration — depending on the available gadget chain (GitHub Advisory, Feedly).

• Network: Unusual or malformed POST requests to ARForms form submission endpoints containing serialized PHP data (e.g., strings beginning with O: or a: patterns in form fields).
• Logs: WordPress or web server access logs showing repeated POST requests to ARForms endpoints with abnormally large or encoded payloads; PHP error logs referencing unexpected class instantiation or magic method calls.
• File System: Unexpected new files (e.g., web shells) in the WordPress installation directory; missing or modified core WordPress files indicating arbitrary file deletion.
• Process: Unusual child processes spawned by the web server process (e.g., bash, curl, wget) following form submission activity.

Update the ARForms plugin to a version newer than 1.8.5 as soon as a patched release becomes available from the vendor (GitHub Advisory). In the interim, audit all installed plugins and themes for known PHP gadget chains and remove any that are unnecessary or known to contain POP chains, as this eliminates the precondition for meaningful exploitation. Implement a Web Application Firewall (WAF) with rules to detect and block serialized PHP object payloads in form submissions. Monitor form submission logs for anomalous or oversized payloads (Feedly).

Wordfence included CVE-2024-13784 in their weekly WordPress vulnerability report covering August 10–16, 2026, highlighting it as a critical-severity finding (Wordfence Blog). The vulnerability was also discussed in a Reddit community brief on r/pwnhub as part of a daily CVE digest. No significant independent researcher commentary or vendor statements beyond standard advisory publication have been identified.