CVE-2021-39157 in detect-character-encoding
Summary
by MITRE • 08/25/2021
detect-character-encoding is an open source character encoding inspection library. In detect-character-encoding v0.6.0 and earlier, data matching no charset causes the Node.js process to crash. The problem has been patched in [detect-character-encoding v0.7.0](https://github.com/sonicdoe/detect-character-encoding/releases/tag/v0.7.0). No workaround are available and all users should update to resolve this issue.
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Analysis
by VulDB Data Team • 08/29/2021
The CVE-2021-39157 vulnerability affects the detect-character-encoding library, a widely used open source component for character encoding inspection in Node.js environments. This library serves as a critical utility for applications that need to determine the encoding of text data, making it an essential dependency for many web applications and data processing systems. The vulnerability specifically targets versions 0.6.0 and earlier, where improper handling of certain data inputs leads to application crashes, potentially resulting in denial of service conditions that can severely impact system availability and user experience.
The technical flaw manifests when the library encounters data that does not match any recognized character set during the encoding detection process. This condition causes the Node.js process to terminate abruptly rather than gracefully handling the unexpected input. The vulnerability represents a classic case of improper error handling and lacks proper input validation mechanisms that would allow the library to either recover from malformed data or provide meaningful error messages to calling applications. This behavior violates fundamental security principles and can be exploited by malicious actors to cause service disruption through carefully crafted inputs that trigger the crash condition.
From an operational perspective, this vulnerability poses significant risks to systems that depend on the detect-character-encoding library, particularly those processing untrusted data from external sources such as user uploads, API responses, or file imports. The crash condition can lead to complete application downtime, requiring system administrators to restart services and potentially lose transient data. The lack of available workarounds forces organizations to immediately update their dependencies, creating operational pressure and potential compatibility issues during the upgrade process. This vulnerability is classified as a denial of service condition that can be easily exploited without requiring special privileges or complex attack vectors, making it particularly dangerous in production environments.
The fix implemented in version 0.7.0 addresses the core issue through improved error handling and input validation mechanisms that prevent the Node.js process from crashing when encountering unexpected character encoding data. This remediation aligns with industry best practices for secure coding and follows the principle of fail-safe error handling. Organizations should prioritize updating to version 0.7.0 or later to mitigate this vulnerability, as no alternative mitigation strategies exist. The vulnerability demonstrates the importance of robust input validation and error handling in security-critical libraries, as outlined in CWE-707 and related security standards that emphasize proper exception handling and graceful degradation of service. This incident highlights the critical need for continuous security monitoring and timely patch management across all software dependencies in modern application environments.