# CVE-2026-49402: Deno: Command Injection via spawnSync & spawn on Windows

> Attackers can execute arbitrary commands on Windows by exploiting improper argument quoting in Deno's child_process module when shell mode is enabled.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jun 2026
- **Updated:** 25 Jun 2026
- **Also known as:** GHSA-7xh3-mhg9-jcw8, JLSEC-2026-656

## What is CVE-2026-49402?

CVE-2026-49402 is a high-severity command injection vulnerability in denoland deno, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.10, Deno's node:child_process implementation provided an escapeShellArg() helper used when callers passed shell: true to spawn / spawnSync / exec and friends. On Windows, the helper failed to quote arguments that contained cmd.exe metacharacters and did not neutralize % (which cmd.exe expands even inside double-quoted strings). An attacker who controlled any portion of an argument passed to such a call could inject arbitrary additional commands into the spawned cmd.exe invocation. This vulnerability is fixed in 2.7.10.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-49402?

2 open source packages ship an affected version, including deno. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `deno` | crates.io | All versions | 2.7.10 |
| `deno` | crates.io | All versions | 2.7.10 |

Products: Deno Deno.

## How do I fix CVE-2026-49402?

Upgrade deno to 2.7.10 or later.

## Is CVE-2026-49402 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49402 exists.

## Other vulnerabilities in denoland deno

- [CVE-2023-28445](https://insights.sbomify.com/CVE-2023-28445/): Deno improperly handles resizable ArrayBuffer (critical 10.0)
- [CVE-2022-24783](https://insights.sbomify.com/CVE-2022-24783/): Sandbox bypass leading to arbitrary code execution in Deno (critical 10.0)
- [CVE-2021-32619](https://insights.sbomify.com/CVE-2021-32619/): Static imports inside dynamically imported modules do not adhere to permission checks (critical 9.8)
- [CVE-2026-22863](https://insights.sbomify.com/CVE-2026-22863/): Deno node:crypto doesn't finalize cipher (critical 9.2)
- [CVE-2024-27936](https://insights.sbomify.com/CVE-2024-27936/): Deno interactive permission prompt spoofing via improper ANSI stripping (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49402 and fix it if it is affected.

What it is: CVE-2026-49402 is a high-severity command injection vulnerability in denoland deno, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49402 exists.

Affected packages and fixed versions:
- deno (crates.io): affected all versions; fixed in 2.7.10
- deno (crates.io): affected all versions; fixed in 2.7.10

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-49402/ (Markdown: https://insights.sbomify.com/CVE-2026-49402/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49402
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49402
- OSV: https://osv.dev/vulnerability/CVE-2026-49402

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49402/
Summaries are generated and may contain mistakes; the official description above is the record.