CVE-2026-39973

NameCVE-2026-39973
DescriptionApktool 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
apktool (PTS)bullseye2.5.0+dfsg.1-2fixed
bookworm2.7.0+dfsg-6+deb12u1fixed
trixie2.7.0+dfsg-7fixed
forky, sid2.7.0+dfsg-7.1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
apktoolsource(unstable)(not affected)

Notes

- apktool <not-affected> (Only affects 3.0.1)
https://github.com/iBotPeaches/Apktool/security/advisories/GHSA-m8mh-x359-vm8m
https://github.com/iBotPeaches/Apktool/pull/4041

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