Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Apktool | Apktool | >= 3.0.0, < 3.0.2 |
Related Weaknesses (CWE)
References
- https://github.com/iBotPeaches/Apktool/commit/e10a0450c7afcd9462c0b76bcbff0e7428Patch
- https://github.com/iBotPeaches/Apktool/pull/4041Issue Tracking
- https://github.com/iBotPeaches/Apktool/releases/tag/v3.0.2Product
- https://github.com/iBotPeaches/Apktool/security/advisories/GHSA-m8mh-x359-vm8mVendor AdvisoryMitigation
FAQ
What is CVE-2026-39973?
CVE-2026-39973 is a vulnerability with a CVSS score of 7.1 (HIGH). 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...
How severe is CVE-2026-39973?
CVE-2026-39973 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39973?
Check the references section above for vendor advisories and patch information. Affected products include: Apktool Apktool.