CVE-2026-49983
MEDIUM
MEDIUM
Priority: 0.01
BB Relevance:
35/100
Published: 2026-06-23
Modified: 2026-10-25
First seen: 2026-10-29
Status: active
Attack Surface
Low Complexity
No Interaction
Scope Change
CVSS Vector Breakdown
AV:
Local
AC:
Low
PR:
Low
UI:
None
S:
Changed
C:
Low
I:
Low
A:
None
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.
Weakness Classification (1)
References & Advisories (1)
Vendor Advisory