# CVE-2026-39973

> Vulnerability · severity: **HIGH** (CVSS 7.1).

## Description

Apktool is a tool for reverse engineering Android APK files. In versions 3.0.0 and 3.0.1, a path traversal vulnerability in `brut/androlib/res/decoder/ResFileDecoder.java` allows a maliciously crafted APK to write arbitrary files to the filesystem during standard decoding (`apktool d`). This is a security regression introduced in commit e10a045 (PR #4041, December 12, 2025), which removed the `BrutIO.sanitizePath()` call that previously prevented path traversal in resource file output paths. An attacker can embed `../` sequences in the `resources.arsc` Type String Pool to escape the output directory and write files to arbitrary locations, including `~/.ssh/config`, `~/.bashrc`, or Windows Startup folders, escalating to RCE. The fix in version 3.0.2 re-introduces `BrutIO.sanitizePath()` in `ResFileDecoder.java` before file write operations.

## Key facts

- **CVE ID:** CVE-2026-39973
- **Published:** 2026-04-21
- **CVSS severity:** HIGH
- **CVSS base score:** 7.1
- **CWE codes:** CWE-22

## Affected products

- `apktool:apktool`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39973

## Citation

> AI Analytics. CVE-2026-39973. Retrieved 2026-07-27 from https://api.ai-analytics.org/cve/CVE-2026-39973. Derived from NIST NVD. Licensed CC0.

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