Apktool: Path Traversal to Arbitrary File Write

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.1 · CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-39973: 0.18% estimated exploitation activity in the next 30 days; percentile 7.86 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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. Fix: Re-introduce BrutIO.sanitizePath() in ResFileDecoder.java before file write operations.

Published by the source

23 Apr 2026, 21:24 UTC

Last modified by the source

23 Apr 2026, 21:24 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m8mh-x359-vm8m

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# Patch Next advisory brief: CVE-2026-39973

Advisory: Apktool: Path Traversal to Arbitrary File Write
IDs: CVE-2026-39973, GHSA-m8mh-x359-vm8m
Record: https://patchnext.com/advisories/cve-2026-39973 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apktool:apktool-lib 3.0.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apktool:apktool-lib: affected >= 3.0.0, < 3.0.2; fixed in 3.0.2

## Suggested inspection (read-only)
- Maven org.apktool:apktool-lib: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apktool:apktool-lib.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m8mh-x359-vm8m (GitHub-reviewed advisory GHSA-m8mh-x359-vm8m lists affected ranges: Maven org.apktool:apktool-lib >=3.0.0 <3.0.2)

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