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.
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History
Tue, 23 Jun 2026 18:30:00 +0000
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Tue, 23 Jun 2026 17:30:00 +0000
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| Description | 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. | |
| Title | Deno: process.loadEnvFile() bypasses env permission checks and mutates process.env with only read access | |
| Weaknesses | CWE-863 | |
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-06-23T17:54:51.686Z
Reserved: 2026-06-02T18:30:51.282Z
Link: CVE-2026-49983
Updated: 2026-06-23T17:54:48.554Z
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OpenCVE Enrichment
Updated: 2026-06-23T21:30:07Z