CVE-2026-103831 in TrueLayer Plugin
Summary
by MITRE • 10/06/2026
CVE-2026-103831: Insecure deserialization vulnerability in the Psr16CacheAdapter component of the TrueLayer Magento 2 Plugin, due to the use of PHP's native unserialize() function without restrictions on the classes allowed when retrieving data stored in the cache. An attacker who already has the ability to write manipulated data to the cache backend used by Magento—such as Redis or Memcached—could inject specially crafted PHP objects and trigger their deserialization, potentially leading to arbitrary code execution via gadget strings available in the application environment. Exploitation therefore requires a prerequisite condition that allows writing to the cache infrastructure, either through access to the local file system or to a cache infrastructure accessible from the Magento environment.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as CVE-2026-103831 represents a critical insecure deserialization flaw within the Psr16CacheAdapter component of the TrueLayer Magento 2 Plugin. This security issue stems directly from the implementation's reliance on PHP’s native unserialize() function to retrieve and process data stored in the cache backend, such as Redis or Memcached. The core technical deficiency lies in the absence of any validation or filtering mechanisms for the classes permitted during deserialization. In standard secure coding practices, applications should either avoid unserializing user-controlled input entirely or employ strict allowlists that restrict deserialized objects to a predefined set of safe types. By failing to implement such restrictions, the plugin inadvertently exposes the application environment to arbitrary object injection attacks when an attacker can influence the content stored in the cache layer.
From an operational perspective, this vulnerability allows for remote code execution if specific prerequisite conditions are met. An attacker must first possess the ability to write manipulated data into the cache infrastructure utilized by the Magento instance. This access could be achieved through various vectors, including direct exploitation of other vulnerabilities that allow file system writes, or via network-level access to the Redis or Memcached servers if they are not properly isolated from untrusted networks. Once such access is established, the attacker can inject specially crafted PHP serialized strings containing malicious gadget chains. When the Psr16CacheAdapter subsequently attempts to deserialize this data for legitimate application use, it instantiates these pre-constructed objects, triggering side effects that lead to arbitrary code execution on the server hosting the Magento platform.
This vulnerability aligns with CWE-502, which describes deserialization of untrusted data as a common weakness in software development. The attack pattern is also consistent with MITRE ATT&CK technique T1059, specifically command and script interpretation via PHP, where attackers leverage existing application functionality to execute malicious commands. The severity of this flaw is heightened by the fact that cache backends like Redis are often deployed on high-performance infrastructure, making successful exploitation potentially impactful for both confidentiality and integrity of the e-commerce platform's data and operations.
Mitigation strategies should focus primarily on eliminating the root cause within the plugin codebase. Developers must replace the use of PHP’s native unserialize() with safer alternatives that do not allow arbitrary object instantiation, such as using json_decode() for structured data or implementing a strict class whitelist during deserialization processes. If unserialization is strictly necessary, it should be confined to trusted internal structures where input sources are fully verified and sanitized before storage. Additionally, infrastructure-level controls can provide defense in depth by ensuring that cache servers like Redis and Memcached are not exposed to public networks and require authentication for access. Regular security audits of third-party Magento plugins are essential to identify similar patterns of insecure data handling across the ecosystem.