GHSA-M8MH-X359-VM8M

Vulnerability from github – Published: 2026-04-23 21:24 – Updated: 2026-04-23 21:24
VLAI?
Summary
Apktool: Path Traversal to Arbitrary File Write
Details

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.

Severity ?
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.apktool:apktool-lib"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-39973"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-23T21:24:28Z",
    "nvd_published_at": "2026-04-21T02:16:07Z",
    "severity": "HIGH"
  },
  "details": "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](https://github.com/iBotPeaches/Apktool/commit/e10a0450c7afcd9462c0b76bcbff0e7428b92bdd#diff-cd531ebe1014bfd18185bf21585ca5cdb16fbcb07703ebc47949a1b4e4e36bc3) ([PR #4041](https://github.com/iBotPeaches/Apktool/pull/4041), December 12, 2025), which removed the `BrutIO.sanitizePath()` call that previously prevented path traversal in resource file output paths.\n\nAn 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.\n\n**Fix:** Re-introduce `BrutIO.sanitizePath()` in `ResFileDecoder.java` before file write operations.",
  "id": "GHSA-m8mh-x359-vm8m",
  "modified": "2026-04-23T21:24:28Z",
  "published": "2026-04-23T21:24:28Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/iBotPeaches/Apktool/security/advisories/GHSA-m8mh-x359-vm8m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39973"
    },
    {
      "type": "WEB",
      "url": "https://github.com/iBotPeaches/Apktool/pull/4041"
    },
    {
      "type": "WEB",
      "url": "https://github.com/iBotPeaches/Apktool/commit/e10a0450c7afcd9462c0b76bcbff0e7428b92bdd#diff-cd531ebe1014bfd18185bf21585ca5cdb16fbcb07703ebc47949a1b4e4e36bc3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/iBotPeaches/Apktool"
    },
    {
      "type": "WEB",
      "url": "https://github.com/iBotPeaches/Apktool/releases/tag/v3.0.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Apktool: Path Traversal to Arbitrary File Write"
}


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