CVE-2026-74875 in openssl_encrypt
Summary
by MITRE • 08/17/2026
openssl_encrypt versions before 1.4.0 silently skip JSON schema validation when the jsonschema library is not installed, allowing malformed metadata to be accepted. Attackers can remove the jsonschema package or supply unknown metadata format versions to bypass all schema checks and process malicious data.
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Analysis
by VulDB Data Team • 08/17/2026
The vulnerability in openssl_encrypt prior to version 1.4.0 represents a critical failure in input validation logic that undermines the integrity of system configurations by allowing malformed metadata to be processed without detection. This flaw stems from an improper handling of optional dependencies, specifically the jsonschema library which is intended for validating JSON data against defined schemas. When this external dependency is absent or when attackers manipulate the environment to simulate its absence, the application fails gracefully in a manner that bypasses security controls rather than raising an error or rejecting invalid input. This behavior creates a silent failure mode where the system continues execution with unvalidated data, effectively disabling the primary defense mechanism designed to ensure configuration correctness and safety.
From a technical perspective, this issue is classified under CWE-20 Improper Input Validation because the application does not adequately verify that inputs meet specified requirements before processing them. The root cause lies in conditional logic that checks for the presence of the jsonschema module but lacks a fallback validation mechanism or an explicit fail-safe state when the library is missing. Instead of halting operations to prevent potential exploitation, the code proceeds with default behaviors that accept arbitrary data structures. This allows attackers who have control over the environment variables or package installation status to deliberately remove the validation layer, thereby exposing the system to injection attacks, configuration manipulation, and other downstream consequences associated with untrusted input processing.
The operational impact of this vulnerability is significant as it enables adversaries to bypass integrity checks that are crucial for maintaining secure state management within applications relying on openssl_encrypt. By supplying unknown metadata format versions or ensuring the jsonschema package is not installed, an attacker can inject malicious payloads into configuration files or data streams that would otherwise be rejected by a properly functioning schema validator. This could lead to privilege escalation if the malformed metadata influences authentication logic, denial of service through resource exhaustion caused by invalid processing paths, or complete compromise of application security policies if critical settings are overwritten with unvalidated values. The silent nature of this failure makes it particularly dangerous as standard logging and monitoring systems may not flag these events as anomalous since no explicit error is thrown during the validation phase.
To mitigate this risk, organizations must upgrade to openssl_encrypt version 1.4.0 or later where the developers have addressed the dependency handling logic to ensure that schema validation cannot be bypassed through missing libraries. In environments where upgrading is not immediately feasible, administrators should enforce strict control over installed Python packages and verify the presence of jsonschema in production deployments before application startup. Additionally implementing runtime checks within custom wrappers around openssl_encrypt can provide an additional layer of defense by explicitly validating input structures even if external dependencies are compromised. Regular auditing of dependency trees and integration testing that includes scenarios with missing optional libraries will help identify such silent failure modes early in the development lifecycle, aligning security practices with industry standards for robust application design.