Description

openssl_encrypt versions before 1.4.0 contain a sandbox bypass vulnerability where the plugin sandbox fails to restrict alternative file access methods like pathlib.Path and io.open. Attackers can import pathlib or io modules to read and write arbitrary files, completely bypassing the restricted_open file access controls.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-08-17T11:16:42.993Z",
  "pubdate": "2026-08-17T11:16:42.993Z",
  "executiveSummary": "A sandbox bypass vulnerability exists in openssl_encrypt versions prior to 1.4.0, involving insufficient restrictions within the plugin sandbox environment.\nThe vulnerability allows unauthorized attackers to completely bypass established restricted_open file access controls.\nThe primary impact of this security flaw is the ability to read and write arbitrary files on the underlying filesystem.\nThe affected product is openssl_encrypt, specifically all parser and execution environments running versions below 1.4.0.\nThe risk implications are severe, as successful exploitation compromises the confidentiality and integrity of the host system by granting unauthorized file system access.\nAttacker capabilities include importing standard library modules to interact with the filesystem directly outside the intended security perimeter.\nExploitation requirements include the ability to execute code within the restricted openssl_encrypt plugin context, leveraging available python-like import mechanisms for alternative file access methods.",
  "technicalDetails": "The root cause of the vulnerability stems from an incomplete sandbox implementation in openssl_encrypt versions before 1.4.0, which restricts built-in file access functions but fails to adequately intercept or restrict alternative file access interfaces.\nThe vulnerable component is the plugin sandbox and its associated restricted_open file access control mechanism.\nAffected versions explicitly include all iterations of openssl_encrypt prior to version 1.4.0.\nThe exploitation method relies on the attacker importing alternative modules that provide filesystem interaction capabilities, specifically bypassing custom file open wrappers.\nThe attack flow proceeds as follows: First, the attacker identifies that the primary restricted_open controls block standard file reading vectors. Second, the attacker imports alternative modules such as pathlib or io within the execution context. Third, the attacker instantiates objects or invokes methods via pathlib.Path or io.open. Fourth, the attacker leverages these alternative file access methods to bypass the sandbox restrictions entirely. Finally, the attacker reads or writes arbitrary files on the system depending on their objectives.\nPayload behavior involves invoking low-level I/O operations through the imported io and pathlib modules, circumventing the application-level security filters designed to restrict file operations to designated safe directories.\nPost-exploitation impact includes unauthorized data exposure, configuration tampering, and potential arbitrary code execution or persistence if sensitive system files or application binaries are modified via the arbitrary file write capability.\nAuthentication and privilege requirements depend on the context in which the plugin executes, but standard execution within the vulnerable sandbox is sufficient for an attacker to leverage the import vectors.\nNetwork exposure is dictated by the exposure of the openssl_encrypt plugin interface to untrusted input or execution vectors."
}