{"id":"GHSA-7w8p-chxq-2789","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.","aliases":["CVE-2025-48934"],"modified":"2026-09-10T03:50:24.980985533Z","published":"2025-06-04T21:18:18Z","database_specific":{"nvd_published_at":"2025-06-04T20:15:24Z","cwe_ids":["CWE-201"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2025-06-04T21:18:18Z"},"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"}],"affected":[{"package":{"name":"deno","ecosystem":"crates.io","purl":"pkg:cargo/deno"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.1.13"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/06/GHSA-7w8p-chxq-2789/GHSA-7w8p-chxq-2789.json"}},{"package":{"name":"deno","ecosystem":"crates.io","purl":"pkg:cargo/deno"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.2.0"},{"fixed":"2.2.13"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/06/GHSA-7w8p-chxq-2789/GHSA-7w8p-chxq-2789.json"}},{"package":{"name":"deno_runtime","ecosystem":"crates.io","purl":"pkg:cargo/deno_runtime"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.212.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/06/GHSA-7w8p-chxq-2789/GHSA-7w8p-chxq-2789.json"}}],"schema_version":"1.9.0","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"}]}