CVE-2026-16554 Details

A heap buffer overflow vulnerability has been identified in the cJSON library, specifically in version 1.7.19, within the print_string_ptr() function in cJSON.c. This vulnerability arises on 32-bit platforms due to an integer overflow in the escape_characters counter, which is a 32-bit size_t. The overflow occurs when processing strings with approximately 858,993,460 or more control characters, leading to an underestimated length for the output buffer allocation. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the resulting write loop can overflow the heap allocation. An attacker can exploit this vulnerability by supplying a crafted JSON string to an application that uses cJSON on a 32-bit platform, potentially causing a heap buffer overflow that could be exploited for remote code execution, information disclosure, or denial of service.