ghsa-7w8p-chxq-2789
Vulnerability from github
5.5 (Medium) - 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
Summary
The Deno.env.toObject method ignores any variables listed in the --deny-env option of the deno run command. When looking at the documentation of the --deny-env option this might lead to a false impression that variables listed in the option are impossible to read.
PoC
``` export AWS_SECRET_ACCESS_KEY=my-secret-aws-key
Works as expected. The program stops with a "NotCapable" error message
echo 'console.log(Deno.env.get("AWS_SECRET_ACCESS_KEY"));' | deno run \ --allow-env \ --deny-env=AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY -
All enviroment variables are printed and the --deny-env list is completely disregarded
echo 'console.log(Deno.env.toObject());' | deno run \ --allow-env \ --deny-env=AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY - ```
The first example using get exits with the following error:
error: Uncaught (in promise) NotCapable: Requires env access to "AWS_SECRET_ACCESS_KEY", run again with the --allow-env flag
console.log(Deno.env.get("AWS_SECRET_ACCESS_KEY"));
^
at Object.getEnv [as get] (ext:deno_os/30_os.js:124:10)
at file:///$deno$stdin.mts:1:22
The second example using toObject prints all environment variables:
[Object: null prototype] {
...
AWS_SECRET_ACCESS_KEY: "my-secret-aws-key",
...
}
Impact
Software 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.
{
"affected": [
{
"package": {
"ecosystem": "crates.io",
"name": "deno"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.1.13"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "crates.io",
"name": "deno"
},
"ranges": [
{
"events": [
{
"introduced": "2.2.0"
},
{
"fixed": "2.2.13"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "crates.io",
"name": "deno_runtime"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.212.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-48934"
],
"database_specific": {
"cwe_ids": [
"CWE-201"
],
"github_reviewed": true,
"github_reviewed_at": "2025-06-04T21:18:18Z",
"nvd_published_at": "2025-06-04T20:15:24Z",
"severity": "MODERATE"
},
"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 \u0027console.log(Deno.env.get(\"AWS_SECRET_ACCESS_KEY\"));\u0027 | 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 \u0027console.log(Deno.env.toObject());\u0027 | 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.",
"id": "GHSA-7w8p-chxq-2789",
"modified": "2025-07-02T18:31:08Z",
"published": "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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
},
{
"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",
"type": "CVSS_V4"
}
],
"summary": "Deno.env.toObject() ignores the variables listed in --deny-env and returns all environment variables"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.