{"id":"CVE-2025-48934","aliases":["GHSA-7w8p-chxq-2789"],"url":"https://o3.security/vulnerability/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.","published":"2025-06-04T19:21:17.701Z","modified":"2026-08-12T03:51:40.760078837Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"crates.io","name":"deno","fixedVersion":"2.1.13"},{"ecosystem":"crates.io","name":"deno","fixedVersion":"2.2.13"},{"ecosystem":"crates.io","name":"deno_runtime","fixedVersion":"0.212.0"}],"fix":{"url":"https://github.com/denoland/deno/commit/2959e083912420988066a001c2b2d6732a1b562f","label":"denoland/deno@2959e08"},"references":[{"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":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/48xxx/CVE-2025-48934.json"},{"type":"ADVISORY","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":"FIX","url":"https://github.com/denoland/deno/commit/2959e083912420988066a001c2b2d6732a1b562f"},{"type":"FIX","url":"https://github.com/denoland/deno/commit/946ccda1aa19a00c478a5e6826b75053b050d753"},{"type":"FIX","url":"https://github.com/denoland/deno/pull/29079"},{"type":"PACKAGE","url":"https://github.com/denoland/deno"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:40.760078837Z"}}