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.
CVSS Score
5.3
EPSS Score
0.001
Published
2025-06-04
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Starting in version 1.41.3 and prior to versions 2.1.13, 2.2.13, and 2.3.2, `deno run --allow-read --deny-read main.ts` results in allowed, even though 'deny' should be stronger. The result is the same with all global unary permissions given as `--allow-* --deny-*`. This only affects a nonsensical combination of flags, so there shouldn't be a real impact on the userbase. Users may upgrade to version 2.1.13, 2.2.13, or 2.3.2 to receive a patch.
CVSS Score
5.3
EPSS Score
0.0
Published
2025-06-04
Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading `/proc/self/environ` may provide access equivalent to `--allow-env`, and writing `/proc/self/mem` may provide access equivalent to `--allow-all`. Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox. Users who run code with `--allow-read` or `--allow-write` may unexpectedly end up granting additional permissions via file-system operations. Deno 1.43 and above require explicit `--allow-all` access to read or write `/etc`, `/dev` on unix platform (as well as `/proc` and `/sys` on linux platforms), and any path starting with `\\` on Windows.
CVSS Score
8.4
EPSS Score
0.001
Published
2024-05-07