Deno: process.loadEnvFile() bypasses env permission checks and mutates process.env with only read access

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, environment access is gated by the env permission. You can deny it with --deny-env, or restrict it to a specific allowlist with --allow-env=FOO,BAR. The expectation is that a program running without env permission cannot change process.env. process.loadEnvFile() (the Node-compatible API for loading variables from a .env file) does not honor this. It only checks that the program has read permission for the dotenv file, then writes every key in that file into the process environment — even when env access is denied. In effect, --allow-read plus a writable or attacker-controlled .env file is enough to defeat --deny-env. This vulnerability is fixed in 2.8.1.

Source published

23 Jun 2026 17:16:17 UTC

Source modified

23 Jun 2026 17:54:51 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 5.2 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, environment access is gated by the env permission. You can deny it with --deny-env, or restrict it to a specific allowlist with --allow-env=FOO,BAR. The expectation is that a program running without env permission cannot change process.env. process.loadEnvFile() (the Node-compatible API for loading variables from a .env file) does not honor this. It only checks that the program has read permission for the dotenv file, then writes every key in that file into the process environment — even when env access is denied. In effect, --allow-read plus a writable or attacker-controlled .env file is enough to defeat --deny-env. This vulnerability is fixed in 2.8.1.

Source published

Jun 23, 2026, 5:16:17 PM (timezone not stated)

Source modified

Jun 23, 2026, 5:54:51 PM (timezone not stated)

Observed here

7 Nov 2026 11:32:23 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.2 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, environment access is gated by the env permission. You can deny it with --deny-env, or restrict it to a specific allowlist with --allow-env=FOO,BAR. The expectation is that a program running without env permission cannot change process.env. process.loadEnvFile() (the Node-compatible API for loading variables from a .env file) does not honor this. It only checks that the program has read permission for the dotenv file, then writes every key in that file into the process environment — even when env access is denied. In effect, --allow-read plus a writable or attacker-controlled .env file is enough to defeat --deny-env. This vulnerability is fixed in 2.8.1.

Source published

23 Jun 2026 18:18:04 UTC

Source modified

25 Oct 2026 23:10:00 UTC

Observed here

27 Oct 2026 13:11:58 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.2 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

## Summary In Deno, environment access is gated by the `env` permission. You can deny it with `--deny-env`, or restrict it to a specific allowlist with `--allow-env=FOO,BAR`. The expectation is that a program running without `env` permission cannot change `process.env`. `process.loadEnvFile()` (the Node-compatible API for loading variables from a `.env` file) does **not** honor this. It only checks that the program has **read** permission for the dotenv file, then writes every key in that file into the process environment — even when `env` access is denied. In effect, **`--allow-read` plus a writable or attacker-controlled `.env` file is enough to defeat `--deny-env`.** ## Am I affected? You are potentially affected if **all** of the following are true: 1. You run Deno **v2.3.0 or newer**. 2. Your program (or any dependency it imports) calls `process.loadEnvFile()` from `node:process`. 3. You rely on Deno's permission model — specifically `--deny-env`, an `--allow-env=…` allowlist, or running without granting `env` — as a security boundary. 4. The `.env` path passed to `loadEnvFile()` can be controlled or modified by a less-trusted party (untrusted input, user-writable directory, third-party dependency, etc.) and is covered by your `--allow-read` grant. If your program does not use `process.loadEnvFile()` at all, or if it already grants full `env` access, this advisory does not change your risk.

Source published

16 Jun 2026 19:04:57 UTC

Source modified

20 Jul 2026 21:15:26 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Publisher rating · MODERATE