Facebook
CVE-2021-24217
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A08:2025 - Software or Data Integrity Failures
ASVS 5.0
V1 - Encoding and Sanitization Safe deserialization, type allowlists
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 8.1 (HIGH). Attack characteristics: network attack vector, high complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could execute arbitrary code through malicious serialized objects by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data making it possible for PHP objects to be supplied creating an Object Injection vulnerability. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Avoid deserializing untrusted data. Use safe serialization formats (JSON). Implement integrity checks and type allowlists.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Deserialization of Untrusted Data (CWE-502), which allows attackers to execute arbitrary code through malicious serialized objects. The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data making it possible for PHP objects to be supplied creating an Object Injection vulnerability. There was also a useable magic method in the plugin that could be used to achieve remote code execution. Affected products include: Facebook. Version information: before 3.0.0.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data making it possible for PHP objects to be supplied creating an Object Injection vulnerability. There was also a useable magic method in the plugin that could be used to achieve remote code execution.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)NVD
React Server Components in React 19.x contain a critical pre-authentication remote code execution vulnerability (CVE-202
Denial of service against HTTP/2 server implementations allows remote unauthenticated attackers to exhaust server resour
A lack of input validation exists in tac_plus prior to commit 4fdf178 which, when pre or post auth commands are enabled,
Due to use of unsafe YAML deserialization logic, an attacker with the ability to modify local YAML configuration files c
The wp_ajax_save_fbe_settings and wp_ajax_delete_fbe_settings AJAX actions of the Facebook for WordPress plugin before 3
An invalid free in Thrift's table-based serialization can cause the application to crash or potentially result in code e
Out-of-bounds write in the (1) mb_detect_encoding, (2) mb_send_mail, and (3) mb_detect_order functions in Facebook HHVM
Infinite recursion in wddx in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vector
The array_*_recursive functions in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown v
Self recursion in compact in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vectors
Integer overflow in StringUtil::implode in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via u
Integer overflow in bcmath in Facebook HHVM before 3.15.0 allows attackers to have unspecified impact via unknown vector
GitHub PoC
Exploit-DB