CVE-2026-49983
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.
- CVSS 3.1
- 5.2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N - EPSS
- 0.1% chance of exploitation in the next 30 days; higher than 3% of CVEs (scores of 2026-10-25)
- CWE
- CWE-863
- Published
- Modified
- Record from
- the NVD, synced
Affected
- deno:deno
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-4c8g-jvcx-v4hv | crates.io | deno | <2.8.1 | 2.8.1 |