Vulnerabilities in pkg:pypi/tuf

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-qp9x-wp8f-qgjj",
  "modified" : "2026-05-28T22:46:13Z",
  "published" : "2026-05-28T22:46:13Z",
  "aliases" : [ ],
  "summary" : "tuf has platform-dependent delegation path matching",
  "details" : "`DelegatedRole._is_target_in_pathpattern` uses `fnmatch.fnmatch` to decide whether a given target path is authorized by a delegation's glob pattern.\n\nPython's `fnmatch.fnmatch` calls `os.path.normcase()` on both arguments before matching. On POSIX hosts `normcase` is the identity function; on Windows hosts `os.path` resolves to `ntpath`, whose `normcase` lowercases its input and replaces `/` with `\\`.\n\nAs a result, python-tuf's delegation *path pattern* matching is case-sensitive on Linux/macOS but case-INSENSITIVE on Windows. This makes the authorization decision for a target dependent on the host operating system of the client running the updater.\n\nThe result on Windows is a TUF specification violation in the python-tuf `ngclient` implementation.\n\n## Vulnerable code\n\n`tuf/api/_payload.py` (HEAD `7ecb67d`):\n\n```python\n1183  @staticmethod\n1184  def _is_target_in_pathpattern(targetpath: str, pathpattern: str) -> bool:\n1185      \"\"\"Determine whether ``targetpath`` matches the ``pathpattern``.\"\"\"\n1186      # We need to make sure that targetpath and pathpattern are pointing to\n1187      # the same directory as fnmatch doesn't threat \"/\" as a special symbol.\n1188      target_parts = targetpath.split(\"/\")\n1189      pattern_parts = pathpattern.split(\"/\")\n1190      if len(target_parts) != len(pattern_parts):\n1191          return False\n1192\n1193      # Every part in the pathpattern could include a glob pattern, that's why\n1194      # each of the target and pathpattern parts should match.\n1195      for target, pattern in zip(target_parts, pattern_parts, strict=True):\n1196          if not fnmatch.fnmatch(target, pattern):\n1197              return False\n1198      return True\n```\n\n`fnmatch.fnmatch` source (Python 3.12, unchanged in current mainline):\n\n```python\ndef fnmatch(name, pat):\n    ...\n    name = os.path.normcase(name)\n    pat = os.path.normcase(pat)\n    return fnmatchcase(name, pat)\n```\n\n## Fix\n\nReplace `fnmatch.fnmatch` with `fnmatch.fnmatchcase`, which is explicitly documented as \"not applying case normalization\", so it behaves identically across platforms.\n\n## Attack\n\n1. A TUF repository with two path-based delegations whose patterns differ only in case — for example, `Foo/*` and `foo/*`.\n2. The \"attacker\" delegation is listed BEFORE the \"legit\" delegation in the delegation order.\n3. The client searches for `foo/something`: on Windows, it will find the \"attacker\" provided target \"Foo/something\".\n\n\n## Exploitability caveats \n\n* The attack needs a repository configuration with case-colliding delegation path patterns. The attacker must control one of the delegated roles.\n* Delegation ordering matters: the attacker-controlled role must be visited BEFORE the legit role in the pre-order walk.\n* The client must run on Windows. No effect on Linux/macOS.\n\n## Credit\n\nReporter: Koda Reef @kodareef5 \nAdvisory edits: Jussi Kukkonen @jku",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "tuf"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "7.0.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 6.0.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/theupdateframework/python-tuf/security/advisories/GHSA-qp9x-wp8f-qgjj"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/theupdateframework/python-tuf"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/theupdateframework/python-tuf/releases/tag/v7.0.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-178" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-28T22:46:13Z",
    "nvd_published_at" : null
  }
}