What’s Vulnerable › Vulnerabilities

CVE-2026-39973: Apktool: Path Traversal to Arbitrary File Write

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-21 · updated 2026-10-26
• Weakness: CWE-22

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.

Affected products

• iBotPeaches Apktool: from 3.0.0 before 3.0.2 — fixed in 3.0.2

How to fix

Upgrade to a fixed version: iBotPeaches Apktool 3.0.2. Check the vendor advisory for mitigations.

References

• https://github.com/iBotPeaches/Apktool/commit/e10a0450c7afcd9462c0b76bcbff0e7428b92bdd#diff-cd531ebe1014bfd18185bf21585ca5cdb16fbcb07703ebc47949a1b4e4e36bc3
• https://github.com/iBotPeaches/Apktool/pull/4041
• https://github.com/iBotPeaches/Apktool/releases/tag/v3.0.2
• https://github.com/iBotPeaches/Apktool/security/advisories/GHSA-m8mh-x359-vm8m

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