CVE-2021-3822 in jsoneditor
Summary
by MITRE • 09/27/2021
jsoneditor is vulnerable to Inefficient Regular Expression Complexity
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/02/2021
The jsoneditor vulnerability CVE-2021-3822 represents a critical security flaw in the jsoneditor library that falls under the category of inefficient regular expression complexity. This vulnerability is classified as a CWE-1321 - Inefficient Regular Expression Complexity, which specifically addresses the risk of regular expressions that can be exploited to cause denial of service through excessive computational resources. The vulnerability stems from the library's handling of regular expressions during JSON parsing operations, where maliciously crafted input can trigger exponential time complexity in regular expression matching algorithms. When attackers provide specially constructed JSON data containing complex nested structures or repetitive patterns, the regular expression engine can experience dramatic performance degradation, potentially leading to system resource exhaustion and service disruption.
The technical implementation of this vulnerability occurs within the jsoneditor's parsing logic where regular expressions are used to validate and process JSON structure elements. The library employs regular expressions to identify and parse various JSON components including strings, numbers, booleans, and null values. When these regular expressions contain patterns that are susceptible to catastrophic backtracking, an attacker can craft input that causes the regular expression engine to perform an exponential number of operations. This behavior is particularly dangerous in environments where jsoneditor is used for processing untrusted input, as the computational overhead can quickly escalate from milliseconds to hours or even days of processing time. The vulnerability manifests as a denial of service condition where legitimate requests cannot be processed due to the excessive resource consumption required to evaluate the malicious regular expressions.
The operational impact of CVE-2021-3822 extends beyond simple service disruption to potentially compromise entire application availability and user experience. Applications that utilize jsoneditor for processing user-generated content, API request handling, or configuration file parsing become vulnerable to attacks that can exhaust system resources such as CPU cycles, memory, and processing time. This vulnerability is particularly concerning in web applications and server-side environments where jsoneditor might be processing requests from untrusted sources without proper input sanitization. The attack surface is broad as jsoneditor is commonly integrated into various development tools, configuration management systems, and web applications that handle JSON data. Organizations using this library in production environments may experience cascading failures where a single malicious request can bring down entire services or make systems unresponsive for extended periods.
Mitigation strategies for CVE-2021-3822 focus on both immediate remediation and long-term architectural improvements. The primary recommendation involves updating to the latest version of jsoneditor where the vulnerable regular expressions have been replaced with more efficient alternatives that prevent catastrophic backtracking scenarios. Organizations should also implement input validation and sanitization measures that filter or reject suspicious JSON patterns before they reach the vulnerable parsing logic. Additional protective measures include implementing rate limiting, request timeouts, and resource monitoring to detect and prevent exploitation attempts. From a defensive perspective, implementing proper security controls such as web application firewalls and input validation layers can provide additional protection against exploitation attempts. The vulnerability also highlights the importance of conducting regular security assessments of third-party libraries and dependencies, as well as maintaining up-to-date security patches across all application components. This case demonstrates the critical need for security professionals to consider regular expression performance implications when designing systems that process untrusted data, aligning with ATT&CK technique T1496 - Resource Hijacking which covers malicious use of system resources for exploitation purposes.