Description

openssl_encrypt versions before 1.4.0 contain a sandbox escape vulnerability in IsolatedPluginExecutor that exposes Python type objects in restricted exec() builtins. Attackers can traverse the Python class hierarchy via __class__.__mro__.__subclasses__() to access system functions and execute arbitrary OS commands.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-17T11:16:44.917Z",
  "pubdate": "2026-08-17T11:16:44.917Z",
  "executiveSummary": "A critical sandbox escape vulnerability exists within openssl_encrypt versions prior to 1.4.0, specifically located in the IsolatedPluginExecutor component.\nThe flaw allows unauthorized attackers to bypass security restrictions imposed on restricted exec() builtins by exposing raw Python type objects.\nSuccessful exploitation of this vulnerability enables malicious actors to traverse the Python class hierarchy and gain unauthorized access to underlying system functions.\nThe primary impact of this security deficiency is remote code execution, granting attackers the capability to execute arbitrary operating system commands within the host environment.\nThis vulnerability poses a severe risk to confidentiality, integrity, and availability, particularly in multi-tenant or plugin-based architectures where sandboxing is relied upon to isolate untrusted code execution.\nAttacker capabilities include full system compromise depending on the privileges of the process running the vulnerable IsolatedPluginExecutor component.\nRemediation requires upgrading openssl_encrypt to version 1.4.0 or later to ensure proper hardening of the restricted execution environment.",
  "technicalDetails": "The vulnerability resides in the IsolatedPluginExecutor component of openssl_encrypt versions before 1.4.0.\nThe root cause stems from improper sanitization and exposure of Python type objects within restricted exec() builtins, which fails to adequately restrict object introspection and scope traversal.\nThe exploitation method relies on Python dynamic introspection features, specifically leveraging the __class__ attribute, the Method Resolution Order (__mro__), and the __subclasses__() method.\nDuring the attack flow, an adversary submits malicious input or plugin code that executes within the constrained execution context of the IsolatedPluginExecutor.\nBecause the sandbox improperly exposes base type objects, the attacker traverses the Python class hierarchy using __class__.__mro__.__subclasses__() to locate loaded modules or classes capable of executing system-level operations, such as subprocess handlers or file system access interfaces.\nOnce a suitable subclass or built-in module is reached, the payload invokes system functions to execute arbitrary OS commands.\nThe affected component is IsolatedPluginExecutor within openssl_encrypt versions < 1.4.0.\nAuthentication and privilege requirements depend on how the plugin execution interface is exposed, but local or remote attackers capable of supplying plugin code can trigger the flaw.\nPost-exploitation impact includes arbitrary command execution, potential lateral movement, data exfiltration, and full host compromise."
}