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

> Unauthenticated attackers can exploit Host header injection in Craft CMS to perform Server-Side Request Forgery via the resource-js endpoint.

- **Severity:** Medium 5.5 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Apr 2026
- **Updated:** 22 Apr 2026
- **Also known as:** GHSA-95wr-3f2v-v2wh

## What is CVE-2026-41130?

CVE-2026-41130 is a medium-severity server-side request forgery vulnerability in craftcms cms, published on 21 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official 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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-41130?

4 open source packages ship an affected version, including craftcms/cms.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `craftcms/cms` | Packagist | From 4.0.0-RC1 | 4.17.9 |
| `craftcms/cms` | Packagist | From 4.0.0-RC1 | 4.17.9 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.9.15 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.9.15 |

## How do I fix CVE-2026-41130?

Upgrade craftcms/cms to a fixed version for your release line: 4.17.9 or 5.9.15.

## Is CVE-2026-41130 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41130 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41130 and fix it if it is affected.

What it is: CVE-2026-41130 is a medium-severity server-side request forgery vulnerability in craftcms cms, published on 21 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41130 exists.

Affected packages and fixed versions:
- craftcms/cms (Packagist): affected from 4.0.0-RC1; fixed in 4.17.9
- craftcms/cms (Packagist): affected from 4.0.0-RC1; fixed in 4.17.9
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.9.15
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.9.15

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-2026-41130/ (Markdown: https://insights.sbomify.com/CVE-2026-41130/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41130
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41130
- OSV: https://osv.dev/vulnerability/CVE-2026-41130

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41130/
Summaries are generated and may contain mistakes; the official description above is the record.