Integer Overflow (Wraparound) vulnerability in the xmlBuildQName() function in libxml2. The flaw arises due to unsafe arithmetic when concatenating XML name components using the lengths of prefix and local name. These lengths, originally size_t, are cast to int, leading to incorrect calculations when values are large. If exploited, the function can perform a memcpy with an extremely large size, causing a stack buffer overflow. This vulnerability is remotely exploitable if the attacker can influence XML content passed to affected applications, potentially resulting in denial of service.