CVE-2018-19200 in uriparser
Summary
by MITRE
An issue was discovered in uriparser before 0.9.0. UriCommon.c allows attempted operations on NULL input via a uriResetUri* function.
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Analysis
by VulDB Data Team • 06/05/2023
The vulnerability identified as CVE-2018-19200 resides within the uriparser library version 0.8.9 and earlier, representing a critical security flaw that enables unauthorized operations on null input parameters. This issue specifically affects the UriCommon.c component of the library, which is responsible for managing URI parsing operations and maintaining consistent internal state across various URI manipulation functions. The root cause stems from inadequate input validation within the uriResetUri* family of functions, which are designed to reset URI structures to their initial states but fail to properly handle null pointer references.
The technical implementation of this vulnerability occurs when the uriResetUri* functions receive null input parameters, allowing attackers to potentially execute operations against uninitialized memory locations or trigger undefined behavior within the parsing engine. This flaw creates a pathway for memory corruption that can be exploited through carefully crafted input sequences, particularly when applications using uriparser process external URI data without proper validation. The vulnerability manifests as a potential denial of service condition or more severe memory corruption that could enable arbitrary code execution depending on the specific usage context and underlying system architecture. According to CWE classification, this represents a CWE-476: NULL Pointer Dereference, which directly maps to the fundamental flaw where the code attempts to access memory through a null pointer reference.
The operational impact of CVE-2018-19200 extends across numerous applications and systems that depend on the uriparser library for URI processing, including web browsers, network security tools, and application servers that handle URI validation and parsing. Attackers can leverage this vulnerability by providing null inputs to functions that expect valid URI structures, potentially causing application crashes, memory corruption, or in more sophisticated attack scenarios, arbitrary code execution within the context of the affected application. The vulnerability is particularly concerning in environments where uriparser is used to process untrusted input from external sources, as it provides a direct vector for exploitation without requiring complex attack chains. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving memory corruption and privilege escalation, potentially enabling adversaries to move laterally within compromised systems.
Mitigation strategies for CVE-2018-19200 primarily involve upgrading to uriparser version 0.9.0 or later, where the null pointer validation has been implemented within the uriResetUri* functions. Organizations should prioritize patching affected systems and reviewing their codebases to ensure proper input validation is implemented when using uriparser functions. Additionally, implementing defensive programming practices such as input sanitization, proper error handling, and runtime checks can provide additional layers of protection. Security teams should monitor their environments for applications using vulnerable versions of uriparser and conduct thorough testing of patched versions to ensure compatibility and stability. The vulnerability also highlights the importance of following secure coding practices and maintaining up-to-date third-party libraries to prevent similar issues from occurring in other components of the software supply chain.