Description

openssl_encrypt versions before 1.4.0 contain a plugin sandbox bypass vulnerability where the PluginImportGuard blocks a different set of modules than the AST analyzer's DANGEROUS_MODULES set. Attackers can bypass AST analysis through string obfuscation or encoding to import unblocked dangerous modules like sys, shutil, multiprocessing, importlib, and pickle for arbitrary code execution.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-17T11:16:43.390Z",
  "pubdate": "2026-08-17T11:16:43.390Z",
  "executiveSummary": "openssl_encrypt versions before 1.4.0 contain a critical plugin sandbox bypass vulnerability stemming from a discrepancy in module restriction mechanisms. Specifically, the PluginImportGuard and the AST analyzer's DANGEROUS_MODULES set enforce inconsistent security boundaries, allowing unauthorized imports.\nThis vulnerability allows threat actors to bypass static Abstract Syntax Tree (AST) analysis controls through various string obfuscation and encoding techniques. By circumventing these detection mechanisms, attackers can successfully import sensitive and unrestricted dangerous modules.\nThe successful exploitation of this flaw leads directly to arbitrary code execution within the context of the affected application. This introduces severe risk implications, including full system compromise, data exfiltration, and unauthorized execution of privileged commands.\nAttackers capable of supplying crafted input or executing plugins can leverage modules such as sys, shutil, multiprocessing, importlib, and pickle. Exploitation relies on abusing the divergence in validation logic between the import guard and the AST analyzer to evade detection.",
  "technicalDetails": "The vulnerability resides within the validation architecture of openssl_encrypt prior to version 1.4.0, specifically in how the AST analyzer and the PluginImportGuard evaluate and restrict module imports. The root cause of the flaw is an architectural inconsistency where the DANGEROus_MODULES set utilized by the AST analyzer does not synchronize or align with the restrictions enforced by the PluginImportGuard.\nDuring the static analysis phase, the AST analyzer scans the input code for forbidden module references defined in DANGEROUS_MODULES. However, because attackers can employ string obfuscation, dynamic evaluation, or various encoding schemes (such as hex, base64, or custom string manipulation), the static analyzer fails to recognize the blacklisted identifiers. Simultaneously, the PluginImportGuard evaluates imports against a disjointed or misconfigured blocklist, failing to intercept the obfuscated modules once execution or secondary import resolution takes place.\nThe attack flow proceeds sequentially as follows: First, an attacker crafts malicious input containing obfuscated or encoded references to dangerous modules that are blocked by the AST analyzer but overlooked or permitted by the inconsistent PluginImportGuard logic. Second, the payload passes the static AST analysis phase due to the obfuscation bypassing pattern matching. Third, during execution or secondary resolution via mechanisms like importlib, the unblocked dangerous modules—including sys, shutil, multiprocessing, and pickle—are successfully imported into the runtime environment.\nThe vulnerable components involve the AST analyzer and PluginImportGuard modules within openssl_encrypt versions prior to 1.4.0. This security boundary failure permits the invocation of powerful system utilities and serialization frameworks. Consequently, attackers achieve arbitrary code execution, enabling them to manipulate file systems via shutil, spawn parallel execution threads via multiprocessing, leverage system internals via sys, and deserialize arbitrary objects via pickle to execute arbitrary payloads."
}