EUVD-2026-243015

fkie_cve-2025-48934

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to versions 2.1.13 and 2.2.13, 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. 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. Versions 2.1.13 and 2.2.13 contains a patch.

GHSA-7w8p-chxq-2789 — Deno.env.toObject() ignores the variables listed in --deny-env and returns all environment variables

Affected: crates.io: deno, crates.io: deno_runtime

### Summary The [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.

### 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 bo…

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EUVD-2026-243015

fkie_cve-2025-48934

GHSA-7w8p-chxq-2789 — Deno.env.toObject() ignores the variables listed in --deny-env and returns all environment variables