CVE-2020-37071 in Craft
Summary
by MITRE • 02/04/2026
CraftCMS 3 vCard Plugin 1.0.0 contains a deserialization vulnerability that allows unauthenticated attackers to execute arbitrary PHP code through a crafted payload. Attackers can generate a malicious serialized payload that triggers remote code execution by exploiting the plugin's vCard download functionality with a specially crafted request.
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Analysis
by VulDB Data Team • 02/04/2026
The vulnerability identified as CVE-2020-37071 affects the CraftCMS 3 vCard Plugin version 1.0.0 and represents a critical deserialization flaw that enables unauthenticated remote code execution. This vulnerability resides within the plugin's vCard download functionality, where the application improperly handles serialized data without adequate validation or sanitization measures. The flaw allows attackers to craft malicious payloads that, when processed by the vulnerable plugin, trigger arbitrary PHP code execution on the affected server. The attack vector is particularly concerning as it requires no authentication credentials, making it accessible to any attacker who can interact with the target system.
The technical root cause of this vulnerability aligns with CWE-502, which specifically addresses deserialization of untrusted data as a security weakness. When the plugin processes vCard download requests, it deserializes user-supplied data without implementing proper input validation or secure deserialization practices. This creates an opportunity for attackers to inject malicious serialized objects that, upon deserialization, execute arbitrary commands on the server. The vulnerability exploits the trust placed in serialized data and demonstrates how insecure deserialization can lead to complete system compromise. The attacker's payload can include PHP objects designed to execute system commands, establish reverse shells, or perform other malicious activities that directly impact the server's integrity and confidentiality.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and data exfiltration capabilities. An attacker who successfully exploits this vulnerability can gain persistent access to the affected CraftCMS installation, potentially leading to unauthorized data access, modification, or deletion. The vulnerability affects not only the specific plugin but also the broader CraftCMS platform, as successful exploitation can provide attackers with a foothold for further reconnaissance and lateral movement within the network infrastructure. Organizations running vulnerable versions of CraftCMS 3 with the vCard plugin face significant risk of unauthorized access, data breaches, and potential service disruption. The unauthenticated nature of the attack means that defenders have no opportunity to detect or prevent the exploitation through standard access controls, making this vulnerability particularly dangerous in environments with exposed web services.
Mitigation strategies for CVE-2020-37071 should prioritize immediate patching of the affected CraftCMS 3 vCard Plugin to version 1.0.1 or later, which contains the necessary security fixes. Organizations should also implement network-level protections such as web application firewalls that can detect and block malicious serialized payload attempts. Additional defensive measures include disabling unnecessary plugin functionality, implementing strict input validation for all user-supplied data, and monitoring system logs for suspicious deserialization activity. Security teams should also conduct comprehensive vulnerability assessments to identify other potentially vulnerable components within their CraftCMS installations and ensure that all plugins and core software remain up to date with the latest security patches. The ATT&CK framework categorizes this vulnerability under T1203, which deals with Exploitation for Client Execution, highlighting the need for comprehensive endpoint protection and application security controls. Organizations should also consider implementing automated security scanning tools that can detect insecure deserialization patterns and provide early warning of potential exploitation attempts.