Craft CMS has a host header injection leading to SSRF via resource-js endpoint

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

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 · score source

EPSS

• CVE-2026-41130: 0.33% estimated exploitation activity in the next 30 days; percentile 26.07 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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). Details The vulnerability exists in AppController::actionResourceJs(). The function validates that the url parameter starts with assetManager-baseUrl. However, baseUrl is derived from the current request host. If trustedHosts is not configured, the Host header is fully attacker-controlled. Attack chain: 1. Attacker sends request with controlled Host header. 2. Application derives baseUrl from the malicious Host. 3. url parameter is required to start with this baseUrl. 4. Validation…

Published by the source

14 Apr 2026, 23:36 UTC

Last modified by the source

24 Apr 2026, 20:42 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-95wr-3f2v-v2wh

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# Patch Next advisory brief: CVE-2026-41130

Advisory: Craft CMS has a host header injection leading to SSRF via resource-js endpoint
IDs: CVE-2026-41130, GHSA-95wr-3f2v-v2wh
Record: https://patchnext.com/advisories/cve-2026-41130 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: craftcms/cms 5.9.15, 4.17.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist craftcms/cms: affected >= 5.0.0-RC1, <= 5.9.14; >= 4.0.0-RC1, <= 4.17.8; fixed in 4.17.9, 5.9.15

## Suggested inspection (read-only)
- Packagist craftcms/cms: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on craftcms/cms.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-95wr-3f2v-v2wh (GitHub-reviewed advisory GHSA-95wr-3f2v-v2wh lists affected ranges: Packagist craftcms/cms >=5.0.0-RC1 =4.0.0-RC1 <=4.17.8)

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