CVE-2026-39973 Apktool: Path Traversal to Arbitrary File Write
A malicious APK can exploit path traversal in Apktool to write arbitrary files, potentially leading to remote code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-39973?
CVE-2026-39973 is a high-severity path traversal vulnerability in iBotPeaches Apktool, published on 21 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-22
Which versions are affected by CVE-2026-39973?
2 open source packages ship an affected version, including org.apktool:apktool-lib. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.apktool:apktool-lib Maven | From 3.0.0 | 3.0.2 |
org.apktool:apktool-lib Maven | From 3.0.0 | 3.0.2 |
Products include Apktool Apktool.
How do I fix CVE-2026-39973?
Upgrade org.apktool:apktool-lib to 3.0.2 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-39973 being exploited?
There is no known exploitation of CVE-2026-39973 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in iBotPeaches Apktool
Sources
Also known as GHSA-m8mh-x359-vm8m, UBUNTU-CVE-2026-39973.