CVE-2026-42471
Published: 01 May 2026
Summary
CVE-2026-42471 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability. Its CVSS base score is 8.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 15.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-7 (Boundary Protection) and SI-10 (Information Input Validation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Timely remediation of the unsafe unserialize() call in MixPHP sync-invoke client directly eliminates the deserialization vulnerability enabling client-side RCE.
Validates and error-handles untrusted server response data before deserialization to block malicious payloads that lead to RCE.
Restricts outbound connections from the MixPHP client to only trusted servers, preventing exposure to malicious responses exploiting the deserialization flaw.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The unsafe deserialization in the MixPHP sync-invoke client directly enables remote code execution when connecting to a malicious server, mapping to Exploitation for Client Execution (T1203) as the primary technique for achieving arbitrary code execution on the client.
NVD Description
Unsafe deserialization vulnerability in MixPHP Framework 2.x thru 2.2.17. The sync-invoke client (Connection.php:76) calls unserialize() on data received from the server response, enabling client-side RCE if connecting to a malicious server.
Deeper analysisAI
CVE-2026-42471 is an unsafe deserialization vulnerability in the MixPHP Framework versions 2.x through 2.2.17. The issue affects the sync-invoke client component, specifically in Connection.php at line 76, where it invokes the unserialize() function on data received from a server response. This flaw, classified under CWE-502, has a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H), highlighting high impact on confidentiality, integrity, and availability.
Attackers can exploit this vulnerability by operating a malicious server that a victim’s MixPHP sync-invoke client connects to. No privileges or user interaction are required, though the attack demands high complexity and network access. Successful exploitation enables remote code execution (RCE) on the client side, as the unserialized data from the server can trigger arbitrary code execution in the client's PHP environment.
References point to a GitHub gist (https://gist.github.com/sgInnora/fa46386840fe978a30d7e53c458f2975), the MixPHP repository (https://github.com/mix-php/mix), and the Server.php source file in version 2.2.17 (https://github.com/mix-php/mix/blob/v2.2.17/src/sync-invoke/src/Server.php), which may provide proof-of-concept details or code context, though no explicit patch or mitigation guidance is detailed in the CVE description.
Details
- CWE(s)