What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-06-04 · updated 2026-06-17
• Weakness: CWE-201

Description

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.

Affected products

• denoland deno: before 2.1.13; from 2.2.0 before 2.2.13 — fixed in 2.1.13, 2.2.13

How to fix

Upgrade to a fixed version: denoland deno 2.1.13, 2.2.13. Check the vendor advisory for mitigations.

References

• https://docs.deno.com/api/deno/~/Deno.Env.toObject
• https://docs.deno.com/runtime/fundamentals/security/#environment-variables
• https://github.com/denoland/deno/commit/2959e083912420988066a001c2b2d6732a1b562f
• https://github.com/denoland/deno/commit/946ccda1aa19a00c478a5e6826b75053b050d753
• https://github.com/denoland/deno/pull/29079
• https://github.com/denoland/deno/security/advisories/GHSA-7w8p-chxq-2789
• https://github.com/denoland/deno/security/advisories/GHSA-7w8p-chxq-2789

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