A path handling issue was addressed with improved logic. This issue is fixed in macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, macOS Tahoe 26.5. An app may be able to observe unprotected user data.
The following code is for security research and authorized testing only.
python
#!/usr/bin/env python3
"""
Conceptual Proof of Concept (PoC) for CVE-2026-39871.
This script simulates how a path handling issue might allow an app
to access unprotected user data outside its sandbox.
Note: This is a simulation based on the vulnerability description.
"""
import os
def simulate_vulnerable_path_check(requested_path):
"""
Simulates a vulnerable path handling logic in macOS.
In a vulnerable state, the system might fail to resolve
canonical paths correctly, allowing access to restricted data.
"""
print(f"[*] App requesting access to: {requested_path}")
# Simulate the vulnerable logic: insufficient canonicalization
# Real vulnerability would be in the kernel/framework C code.
base_path = "/var/mobile/Applications/MyApp/Data"
# Vulnerable check: does not resolve '../' properly before checking prefix
if requested_path.startswith(base_path) or "../" in requested_path:
# In the real vulnerability, the OS might skip the strict check
# due to logic flaw, allowing the traversal.
resolved_path = os.path.normpath(requested_path)
print(f"[!] VULNERABLE LOGIC: Access allowed to resolved path: {resolved_path}")
# Simulate reading sensitive data
if "PrivateUserData" in resolved_path:
return "SENSITIVE_DATA_EXPOSED: User_Credentials.txt"
else:
print("[-] Access denied by sandbox.")
return None
# Attack Scenario: Crafting a path to escape sandbox
# The app tries to access user data outside its container
malicious_path = "/var/mobile/Applications/MyApp/Data/../../../Users/Shared/PrivateUserData"
print("--- Testing CVE-2026-39871 PoC ---")
result = simulate_vulnerable_path_check(malicious_path)
if result:
print(f"[+] EXPLOIT SUCCESSFUL: {result}")
else:
print("[-] Exploit failed.")