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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.5 · 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 · score source

EPSS

• CVE-2025-48934: 0.44% estimated exploitation activity in the next 30 days; percentile 38.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. PoC The first example using get exits with the following error: The second example using toObject prints all environment variables: Impact 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.

Published by the source

4 Jun 2025, 21:18 UTC

Last modified by the source

2 Jul 2025, 18:31 UTC

Source last checked

26 Oct 2026, 15:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7w8p-chxq-2789

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# Patch Next advisory brief: CVE-2025-48934

Advisory: Deno.env.toObject() ignores the variables listed in --deny-env and returns all environment variables
IDs: CVE-2025-48934, GHSA-7w8p-chxq-2789
Record: https://patchnext.com/advisories/cve-2025-48934 (revision 1, source checked 26 Oct 2026, 15:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: deno_runtime 0.212.0; deno 2.2.13, 2.1.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io deno_runtime: affected < 0.212.0; fixed in 0.212.0
- crates.io deno: affected < 2.1.13; >= 2.2.0, < 2.2.13; fixed in 2.2.13, 2.1.13

## Suggested inspection (read-only)
- crates.io deno_runtime: check the installed version with your package manager.
- crates.io deno: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on deno_runtime, deno.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7w8p-chxq-2789 (GitHub-reviewed advisory GHSA-7w8p-chxq-2789 lists affected ranges: crates.io deno >=0 =2.2.0 =0 <0.212.0)

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