CVE-2017-7867 in International Components for Unicode
Summary
by MITRE
International Components for Unicode (ICU) for C/C++ before 2017-02-13 has an out-of-bounds write caused by a heap-based buffer overflow related to the utf8TextAccess function in common/utext.cpp and the utext_setNativeIndex* function.
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Analysis
by VulDB Data Team • 08/09/2025
The vulnerability identified as CVE-2017-7867 affects International Components for Unicode (ICU) for C/C++ libraries prior to version 2017-02-13, representing a critical heap-based buffer overflow condition that can lead to arbitrary code execution. This flaw resides within the core text processing functionality of ICU, which is widely utilized across numerous applications and systems for internationalization and Unicode text handling. The vulnerability specifically manifests in the utf8TextAccess function located in common/utext.cpp and is exacerbated by the utext_setNativeIndex* function, creating a dangerous combination that can be exploited by attackers to manipulate memory contents.
The technical implementation of this vulnerability stems from inadequate bounds checking within the Unicode text access mechanisms. When applications process UTF-8 encoded text through ICU libraries, the utf8TextAccess function fails to properly validate array indices before performing memory writes, resulting in an out-of-bounds write condition. This occurs because the utext_setNativeIndex* functions do not sufficiently validate input parameters or maintain proper boundary constraints during text position calculations, allowing attackers to craft malicious input that overflows heap-allocated buffers. The vulnerability is particularly concerning as it operates at the core text processing layer, making it potentially exploitable across a broad spectrum of applications that depend on ICU for international text handling.
The operational impact of CVE-2017-7867 extends beyond simple memory corruption, as it represents a severe security weakness that can be leveraged for remote code execution in vulnerable applications. Systems utilizing ICU libraries for text processing, including web browsers, database management systems, application servers, and enterprise software platforms, become susceptible to exploitation. Attackers can potentially manipulate input data to trigger the buffer overflow, leading to memory corruption that may allow for privilege escalation, denial of service conditions, or complete system compromise. The vulnerability's exploitation risk is elevated due to ICU's widespread adoption across multiple software ecosystems and its integration into critical infrastructure components, making it a prime target for advanced persistent threats and zero-day exploits.
Organizations should prioritize immediate remediation by upgrading to ICU version 2017-02-13 or later, which contains the necessary patches to address the bounds checking deficiencies. System administrators should conduct comprehensive vulnerability assessments to identify all applications and services that utilize ICU libraries, particularly those handling untrusted input from external sources. Additional mitigations include implementing strict input validation measures, deploying intrusion detection systems to monitor for exploitation attempts, and considering runtime protections such as stack canaries and address space layout randomization. From a compliance standpoint, this vulnerability aligns with CWE-121 heap-based buffer overflow conditions and may be categorized under ATT&CK technique T1059 for command and scripting interpreter usage, while also potentially supporting lateral movement activities through privilege escalation vectors. Regular security auditing and vulnerability management processes should include monitoring for similar patterns in other Unicode processing libraries and text handling components to prevent analogous issues from emerging in the software supply chain.