CVE-2021-41146: Qutebrowser URL Handler Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vw27-fwjf-5qxm",
  "modified" : "2024-10-16T20:48:13Z",
  "published" : "2021-10-22T16:20:10Z",
  "aliases" : [ "CVE-2021-41146" ],
  "summary" : "Arbitrary command execution on Windows via qutebrowserurl: URL handler",
  "details" : "### Impact\nStarting with qutebrowser v1.7.0, the Windows installer for qutebrowser registers it as a handler for certain URL schemes. With some applications such as Outlook Desktop, opening a specially crafted URL can lead to argument injection, allowing execution of qutebrowser commands, which in turn allows arbitrary code execution via commands such as `:spawn` or `:debug-pyeval`.\n\nOnly Windows installs where qutebrowser is registered as URL handler are affected. It does *not* have to be set as default browser for the exploit to work.\n\n### Patches\nThe issue has been fixed in [qutebrowser v2.4.0](https://github.com/qutebrowser/qutebrowser/releases/tag/v2.4.0) in commit 8f46ba3f6dc7b18375f7aa63c48a1fe461190430.\n\nThe fix also adds additional hardening for potential similar issues on Linux (by adding the new `--untrusted-args` flag to the `.desktop` file), though no such vulnerabilities are known.\n\nBackported patches for older versions are available, but no further releases are planned:\n\n- v1.7.x: d1ceaab\n- v1.8.x: ca7155d\n- v1.9.x: 157d871\n- v1.10.x: 94a6125\n- v1.11.x: 10acfbb\n- v1.12.x: 363a18f\n- v1.13.x: 410f262\n- v1.14.x: e4f4d93\n- v2.0.x: 15a1654\n- v2.1.x: 509ddf2\n- v2.2.x: 03dcba5\n- v2.3.x: 00a694c\n\n(commits are referring to qutebrowser/qutebrowser on GitHub)\n\n### Workarounds\nRemove qutebrowser from the default browser settings entirely, so that it does not handle any kind of URLs. Make sure to remove *all* handlers, including an (accidental) `qutebrowserURL` handler, e.g. using [NirSoft URLProtocolView](https://www.nirsoft.net/utils/url_protocol_view.html).\n\n### Timeline\n2021-10-15: Issue reported via security@qutebrowser.org by Ping Fan (Zetta) Ke of [Valkyrie-X Security Research Group (VXRL)](https://www.vxrl.hk/)\n2021-10-15: Issue confirmed by @The-Compiler (lead developer), author of installer (@bitraid) contacted for help/review\n2021-10-15: CVE assigned by GitHub\n2021-10-15 to 2021-10-17: Fix developed\n2021-10-17: Additional core developer (@toofar) contacted for help/review\n2021-10-21: v2.4.0 released containing the fix\n2021-10-21: Advisory and fix published\n\n### References\nSee the [commit message](https://github.com/qutebrowser/qutebrowser/commit/8f46ba3f6dc7b18375f7aa63c48a1fe461190430) for additional information and references to various similar issues in other projects.\n\n### Acknowledgements\nThanks to Ping Fan (Zetta) Ke of [Valkyrie-X Security Research Group](https://www.vxrl.hk/) (VXRL/@vxresearch) for finding and responsibly disclosing this issue.\n\n### Contact\nIf you have any questions or comments about this advisory, please email [security@qutebrowser.org](mailto:security@qutebrowser.org).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "qutebrowser"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.7.0"
      }, {
        "fixed" : "2.4.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/qutebrowser/qutebrowser/security/advisories/GHSA-vw27-fwjf-5qxm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-41146"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/qutebrowser/qutebrowser/commit/8f46ba3f6dc7b18375f7aa63c48a1fe461190430"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/qutebrowser/PYSEC-2021-382.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/qutebrowser/qutebrowser"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-641", "CWE-77", "CWE-88" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-10-21T20:46:42Z",
    "nvd_published_at" : "2021-10-21T18:15:00Z"
  }
}