# CVE-2026-23644: GO-2026-4332 - esm.sh has a path traversal in extractPackageTarball enables file writes from malicious packages

Source: https://junglewise.ai/threats/cve-2026-23644-esm-sh-has-a-path-traversal-in-extractpackagetarball-enables-file  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-26  
License: CC BY 4.0 with a link back

CVE-2026-23644 · Severity: medium · CVSS 4 · Published 2026-02-26

esm.sh has a path traversal in extractPackageTarball enables file writes from malicious packages

Technologies: [github.com/esm-dev/esm.sh (Go)](https://junglewise.ai/threats/technologies/github-com-esm-dev-esm-sh). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-23644 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-23644 being exploited in the wild.

**How severe is CVE-2026-23644?** Medium severity, with a CVSS score of 4, published 26 February 2026.

**Which products and versions are affected?** github.com/esm-dev/esm.sh (Go) ECOSYSTEM:introduced=0.0.1,last_affected=136, SEMVER:introduced=0,fixed=0.0.0-20260116051925-c62ab83c589e.

**Is there a fix for CVE-2026-23644?** Yes. github.com/esm-dev/esm.sh (Go): upgrade to 0.0.0-20260116051925-c62ab83c589e or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-23644?** Check whether you run github.com/esm-dev/esm.sh (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/esm-dev/esm.sh (Go): upgrade to 0.0.0-20260116051925-c62ab83c589e or later

  ```sh
  go get github.com/esm-dev/esm.sh@v0.0.0-20260116051925-c62ab83c589e
  ```


## Affected products

- github.com/esm-dev/esm.sh (Go) ECOSYSTEM:introduced=0.0.1,last_affected=136, SEMVER:introduced=0,fixed=0.0.0-20260116051925-c62ab83c589e

## Identifiers

- CVE-2026-23644
- GHSA-2657-3c98-63jq
- GO-2026-4332

## Related threats

- [esm-dev esm.sh path traversal in package.json browser field](https://junglewise.ai/threats/cve-2026-44594-esm-dev-esm-sh-path-traversal-in-package-json-browser-field)
- [esm.sh path traversal in legacy router leads to arbitrary file write](https://junglewise.ai/threats/cve-2026-44593-esm-sh-path-traversal-in-legacy-router-leads-to-arbitrary-file)
- [GO-2026-4554 - esm.sh has SSRF localhost/private-network bypass in `/http(s)` module route in github.com/esm-dev/esm.sh](https://junglewise.ai/threats/cve-2026-27730-esm-sh-has-ssrf-localhost-private-network-bypass-in-http-s-module)
- [GO-2026-4545 - esm.sh is vulnerable to full-response SSRF in github.com/esm-dev/esm.sh](https://junglewise.ai/threats/cve-2025-50180-esm-sh-is-vulnerable-to-full-response-ssrf)
- [GO-2025-4139 - esm.sh CDN service has JS Template Literal Injection in CSS-to-JavaScript in github.com/esm-dev/esm.sh](https://junglewise.ai/threats/cve-2025-65026-esm-sh-cdn-service-has-js-template-literal-injection-in-css-to)