CVE-2024-38517 in RapidJSON
Summary
by MITRE • 07/09/2024
Tencent RapidJSON is vulnerable to privilege escalation due to an integer underflow in the `GenericReader::ParseNumber()` function of `include/rapidjson/reader.h` when parsing JSON text from a stream. An attacker needs to send the victim a crafted file which needs to be opened; this triggers the integer underflow vulnerability (when the file is parsed), leading to elevation of privilege.
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Analysis
by VulDB Data Team • 05/05/2026
The vulnerability identified as CVE-2024-38517 affects Tencent RapidJSON, a widely used C++ library for parsing and generating JSON data. This library is implemented as part of the RapidJSON framework and is commonly integrated into various applications that process JSON content. The specific flaw exists within the `GenericReader::ParseNumber()` function located in the `include/rapidjson/reader.h` file, which handles the parsing of numeric values from JSON streams. The integer underflow occurs during the parsing process when the library attempts to handle certain malformed numeric values, creating a condition where arithmetic operations result in values that fall below the minimum representable integer, thereby corrupting memory structures.
The technical implementation of this vulnerability stems from improper input validation within the number parsing routine. When RapidJSON encounters a crafted JSON file containing specially formatted numeric data, the parsing function fails to properly validate integer boundaries during arithmetic calculations. This underflow condition can cause the library to overwrite adjacent memory locations, potentially leading to arbitrary code execution or privilege escalation. The vulnerability is particularly concerning because it operates at the parsing layer, meaning any application using RapidJSON to process untrusted JSON input becomes susceptible to exploitation. The attacker's attack vector requires social engineering to deliver a malicious file to the victim, who must then open or process the file with an application that utilizes RapidJSON for JSON parsing.
The operational impact of CVE-2024-38517 extends beyond simple privilege escalation, as it represents a critical security weakness that can be leveraged for more sophisticated attacks. When an application using RapidJSON processes a malicious JSON file, the integer underflow can corrupt program execution flow, potentially allowing attackers to execute arbitrary code with the privileges of the victim process. This vulnerability aligns with CWE-191, which specifically addresses integer underflow conditions, and can be mapped to ATT&CK technique T1059.007 for scripting languages and T1547.001 for privilege escalation. The attack requires minimal user interaction beyond opening the crafted file, making it particularly dangerous in scenarios where users frequently process JSON documents from untrusted sources, such as email attachments, web downloads, or collaborative platforms.
Mitigation strategies for this vulnerability focus on both immediate patching and defensive programming practices. The primary solution involves updating to the latest version of RapidJSON that contains the patched `GenericReader::ParseNumber()` function with proper integer boundary checks and underflow protection mechanisms. Organizations should implement comprehensive input validation at all levels of their applications, ensuring that JSON parsing libraries are configured to reject malformed numeric values before they reach the vulnerable parsing routines. Additional defensive measures include implementing sandboxing techniques for JSON processing, using memory protection features such as stack canaries and address space layout randomization, and conducting regular security audits of applications that utilize RapidJSON. Network-level controls such as JSON content filtering and application firewalls can also provide additional protection layers to prevent exploitation attempts. Security teams should prioritize patching applications using RapidJSON, particularly those handling user-provided JSON data, and implement monitoring to detect potential exploitation attempts through anomalous parsing behavior.