CVE-2021-46142 in uriparser
Summary
by MITRE • 01/06/2022
An issue was discovered in uriparser before 0.9.6. It performs invalid free operations in uriNormalizeSyntax.
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Analysis
by VulDB Data Team • 01/09/2022
The vulnerability identified as CVE-2021-46142 represents a critical memory safety issue within the uriparser library version 0.9.5 and earlier. This library serves as a URI parsing and normalization component widely utilized across various software systems for handling uniform resource identifiers. The flaw manifests specifically within the uriNormalizeSyntax function which is responsible for normalizing URI syntax according to RFC standards. The issue stems from improper memory management practices where the library executes invalid free operations on memory locations that have either already been freed or were never allocated through the standard allocation mechanisms. This type of vulnerability falls under the category of memory corruption errors and is classified as a CWE-415 Double Free vulnerability according to the Common Weakness Enumeration catalog. The improper free operations can lead to undefined behavior including potential crashes, data corruption, or in some scenarios, arbitrary code execution if attackers can manipulate the memory allocation patterns.
The operational impact of this vulnerability extends across numerous applications and systems that depend on uriparser for URI handling. Software components ranging from web browsers and network utilities to enterprise applications and security tools may be affected when processing malformed URIs or when the library is invoked during URI normalization processes. The vulnerability's exploitation potential increases when the affected library is used in environments where untrusted URI input is processed, such as web applications, network daemons, or any system handling user-provided URI data. Attackers could potentially craft malicious URIs that trigger the invalid free operations, leading to system instability or more severe consequences depending on the execution context. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1499.004 for Endpoint Denial of Service, as it can be leveraged to cause system disruptions or potentially gain unauthorized access through memory corruption exploits.
Mitigation strategies for CVE-2021-46142 primarily involve upgrading to uriparser version 0.9.6 or later where the memory management issues have been resolved through proper implementation of allocation and deallocation routines. Organizations should conduct comprehensive inventory assessments to identify all systems and applications utilizing the vulnerable library and prioritize patching efforts accordingly. Additional defensive measures include implementing input validation and sanitization for URI data, employing memory debugging tools such as valgrind or address sanitizers during development and testing phases, and establishing runtime monitoring to detect anomalous memory behavior. The fix implemented in version 0.9.6 addresses the root cause by ensuring that free operations are only performed on memory that was properly allocated through standard allocation functions and has not been previously freed. Security teams should also consider implementing network segmentation and access controls to limit exposure of systems that process untrusted URI input, while maintaining regular vulnerability scanning to identify other potential instances of the same vulnerability pattern in third-party libraries.