CVE-2025-48934 MEDIUM

CVE-2025-48934: Deno.env.toObject() ignores the variables listed in --deny-env and returns all environment variables

Vendor Denoland
Product deno
Weakness CWE-201
Published June 4, 2025
Last update June 4, 2025

CVSS base score

5.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

June 4, 2025 CVE published
June 4, 2025 Record updated