{"id":"UBUNTU-CVE-2026-39973","details":"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.","modified":"2026-05-20T16:25:38.736127384Z","published":"2026-04-21T02:16:00Z","upstream":["CVE-2026-39973"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-39973"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-39973"}],"affected":[{"package":{"name":"apktool","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.2+dfsg-1","2.0.2+dfsg-2"],"ecosystem_specific":{"binaries":[{"binary_name":"apktool","binary_version":"2.0.2+dfsg-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}},{"package":{"name":"apktool","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.2.4+dfsg-1","2.3.0+dfsg-1","2.3.1+dfsg-1","2.3.4-1~18.04"],"ecosystem_specific":{"binaries":[{"binary_version":"2.3.4-1~18.04","binary_name":"apktool"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}},{"package":{"name":"apktool","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"apktool","binary_version":"2.4.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}},{"package":{"name":"apktool","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.0+dfsg.1-2build1"],"ecosystem_specific":{"binaries":[{"binary_name":"apktool","binary_version":"2.5.0+dfsg.1-2build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}},{"package":{"name":"apktool","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7.0+dfsg-6","2.7.0+dfsg-7"],"ecosystem_specific":{"binaries":[{"binary_name":"apktool","binary_version":"2.7.0+dfsg-7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}},{"package":{"name":"apktool","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7.0+dfsg-7"],"ecosystem_specific":{"binaries":[{"binary_version":"2.7.0+dfsg-7","binary_name":"apktool"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}},{"package":{"name":"apktool","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/apktool?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7.0+dfsg-7","2.7.0+dfsg-7.1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"apktool","binary_version":"2.7.0+dfsg-7.1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39973.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}