CVE-2026-40027: ALEAPP Path Traversal Vulnerability

CVE-2026-40027 Overview

CVE-2026-40027 is a path traversal vulnerability discovered in ALEAPP (Android Logs Events And Protobuf Parser) through version 3.4.0. The vulnerability exists in the NQ_Vault.py artifact parser, which uses attacker-controlled file_name_from values from a database directly as the output filename without proper sanitization. This allows arbitrary file writes outside the intended report output directory, potentially leading to code execution through overwriting executable files or critical configuration.

Critical Impact

An attacker can embed path traversal payloads such as ../../../outside_written.bin in database entries to write files to arbitrary locations on the system, potentially achieving remote code execution by overwriting executable files or configuration.

Affected Products

• ALEAPP (Android Logs Events And Protobuf Parser) versions through 3.4.0
• Systems running vulnerable versions of the NQ_Vault artifact parser
• Forensic analysis environments processing untrusted Android data

Discovery Timeline

• 2026-04-08 - CVE-2026-40027 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2026-40027

Vulnerability Analysis

This path traversal vulnerability (CWE-22) occurs in the NQ_Vault.py artifact parser component of ALEAPP. The parser extracts file_name_from values from a database during forensic analysis operations and uses these values directly as output filenames without validating or sanitizing the input. Since ALEAPP is designed to parse Android logs and artifacts from potentially untrusted sources, an attacker who can control the contents of the database being analyzed can inject malicious path traversal sequences.

The vulnerability enables arbitrary file write operations outside the designated report output directory. When the parser processes a database containing a malicious filename like ../../../outside_written.bin, the file write operation traverses the directory structure and places the file at an attacker-controlled location. This can be weaponized to overwrite system executables, inject malicious scripts into startup directories, or modify configuration files to achieve persistent code execution on the forensic analyst's workstation.

Root Cause

The root cause is improper input validation in the NQ_Vault.py artifact parser. The code directly uses user-controlled database values as filesystem paths without sanitizing or validating them against path traversal sequences. The absence of input validation on the file_name_from field allows directory traversal characters (../) to be processed literally by the filesystem operations.

Attack Vector

The attack requires local access with user interaction. An attacker must craft a malicious Android database containing path traversal payloads in the file_name_from field. When a forensic analyst processes this database using ALEAPP, the malicious payload executes during the artifact parsing phase. The attacker-controlled filename is used directly in file write operations, causing files to be written outside the intended output directory to arbitrary locations on the analyst's system.

 import itertools
+import re
 import string
 from pathlib import Path
 from os.path import join

Source: GitHub Commit Details

The patch introduces the re module to enable regex-based input sanitization, blocking path traversal sequences in the decrypted file write operations.

Detection Methods for CVE-2026-40027

Indicators of Compromise

• Presence of unexpected files written outside ALEAPP's designated report output directories
• Database entries containing path traversal sequences (../, ..\\) in filename fields
• Unusual file modifications to system executables or configuration files during ALEAPP execution
• Evidence of malicious payloads in NQ Vault database artifacts being processed

Detection Strategies

• Monitor file system activity during ALEAPP execution for writes outside expected output directories
• Implement database content scanning to detect path traversal patterns in filename fields before processing
• Use file integrity monitoring (FIM) on critical system directories during forensic analysis operations
• Review ALEAPP processing logs for anomalous file path operations

Monitoring Recommendations

• Configure endpoint detection to alert on file writes containing ../ sequences from ALEAPP processes
• Implement sandbox environments for processing untrusted Android forensic artifacts
• Enable detailed logging of all file system operations during artifact parsing
• Monitor for unexpected modifications to executable files and configuration directories

How to Mitigate CVE-2026-40027

Immediate Actions Required

• Upgrade ALEAPP to a patched version that includes commit 0cafd8fe0027663420eb3d0fa821b2d1a713880d
• Process untrusted Android artifacts in isolated sandbox environments until patching is complete
• Review any forensic analysis performed with vulnerable versions for signs of compromise
• Implement file system access controls to limit write permissions during artifact processing

Patch Information

The vulnerability has been addressed in the official ALEAPP repository. The fix introduces regex-based input validation to sanitize filename inputs and block path traversal sequences in the NQ_Vault artifact parser. The security patch is available via GitHub Pull Request #669 and commit 0cafd8fe0027663420eb3d0fa821b2d1a713880d. Users should update to the latest version of ALEAPP that includes this fix.

Workarounds

• Run ALEAPP in a containerized or sandboxed environment with restricted file system access
• Pre-validate database contents for path traversal patterns before processing with ALEAPP
• Configure strict directory permissions to prevent file writes outside designated output directories
• Use a dedicated, isolated analysis workstation for processing untrusted forensic artifacts

# Configuration example - Run ALEAPP in a restricted directory context
# Create isolated output directory with restricted permissions
mkdir -p /forensics/aleapp_output
chmod 700 /forensics/aleapp_output

# Run ALEAPP with output constrained to isolated directory
python aleapp.py -i /path/to/android_data -o /forensics/aleapp_output

# Verify no files written outside expected directory
find /forensics/aleapp_output -type f -name "*.bin" -ls