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.
The vulnerability has been fixed by the TrueLayer team in version 2.4.3 of the TrueLayer Magento 2 Plugin, which has been publicly available since August 3, 2026.
The fix removes the use of the unserialize() function in the Psr16CacheAdapter component and adopts a JSON-based serialization mechanism, in line with the security practices implemented in the Magento 2 core.
It is recommended to update the plugin to version 2.4.3 or later. It is also recommended to ensure that the caching infrastructure used by Magento does not allow unauthorized write access.