Vulnerabilities in pkg:gem/phlex

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w67g-2h6v-vjgq",
  "modified" : "2026-02-06T19:35:09Z",
  "published" : "2026-02-06T19:35:09Z",
  "aliases" : [ ],
  "summary" : "Phlex XSS protection bypass via attribute splatting, dynamic tags, and href values",
  "details" : "### Impact\n\nDuring a security audit conducted with Claude Opus 4.6 and GPT-5.3-Codex, we identified three specific ways to bypass the XSS (cross-site-scripting) protection built into Phlex.\n\n1. The first bypass could happen if user-provided attributes with string keys were splatted into HTML tag, e.g. `div(**user_attributes)`.\n2. The second bypass could happen if user-provided tag names were passed to the `tag` method, e.g. `tag(some_tag_name_from_user)`.\n3. The third bypass could happen if user’s links were passed to `href` attributes, e.g. `a(href: user_provided_link)`.\n\nAll three of these patterns are meant to be safe and all have now been patched.\n\n### Patches\n\nPhlex has patched all three issues and introduced new tests that run against Safari, Firefox and Chrome.\n\nThe patched versions are:\n\n- [2.4.1](https://rubygems.org/gems/phlex/versions/2.4.1)\n- [2.3.2](https://rubygems.org/gems/phlex/versions/2.3.2)\n- [2.2.2](https://rubygems.org/gems/phlex/versions/2.2.2)\n- [2.1.3](https://rubygems.org/gems/phlex/versions/2.1.3)\n- [2.0.2](https://rubygems.org/gems/phlex/versions/2.0.3)\n- [1.11.1](https://rubygems.org/gems/phlex/versions/1.11.1)\n\nPhlex has also patched the [`main`](https://github.com/yippee-fun/phlex) branch in GitHub.\n\n### Workarounds\nIf a project uses a secure CSP (content security policy) or if the application doesn’t use any of the above patterns, it is not at risk.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "phlex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.4.0.beta1"
      }, {
        "fixed" : "2.4.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "phlex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.3.0"
      }, {
        "fixed" : "2.3.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "phlex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.2.0"
      }, {
        "fixed" : "2.2.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "phlex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.1.0"
      }, {
        "fixed" : "2.1.3"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "phlex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0.beta1"
      }, {
        "fixed" : "2.0.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "phlex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.11.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/yippee-fun/phlex/security/advisories/GHSA-w67g-2h6v-vjgq"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yippee-fun/phlex/commit/1d85da417cb15eb8cb2f54a68d531c9b35d9d03a"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yippee-fun/phlex/commit/556441d5a64ff93f749e8116a05b2d97264468ee"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yippee-fun/phlex/commit/74e3d8610ffabc2cf5f241945e9df4b14dceb97d"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yippee-fun/phlex/commit/9f56ad13bea9a7d6117fdfd510446c890709eeac"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yippee-fun/phlex/commit/fe9ea708672f9fa42526d9b47e1cdc4634860ef1"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/yippee-fun/phlex"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-06T19:35:09Z",
    "nvd_published_at" : null
  }
}