Craft CMS Vulnerable to Authenticated RCE via Twig SSTI - create() function + Symfony Process gadget

Exploitation

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

CVSS 4.0

6.6 · CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2026-28695: 0.66% estimated exploitation activity in the next 30 days; percentile 51.70 (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.

There is an authenticated admin RCE in Craft CMS 5.8.21 via Server-Side Template Injection using the create() Twig function combined with a Symfony Process gadget chain. This bypasses the fix implemented for CVE-2025-57811 (patched in 5.8.7). Required Permissions - Administrator permissions or access to System Messages utility - allowAdminChanges enabled in production (against our security recommendations) or access to System Messages utility Vulnerability Details The create() Twig function exposes Craft::createObject(), which allows instantiation of arbitrary PHP classes with constructor arguments. Combined with the bundled symfony/process dependency, this enables RCE. Attack Vector Admin panel → Settings → Entry Types → Title Format field Proof of Concept Payload Steps to Reproduce 1. Log in as admin 2. Navigate to Settings → Entry Types 3. Edit any entry type’s "Title Format" field 4. Insert the payload above 5. Create/edit an entry of that type 6. Command executes, output appears…

Published by the source

3 Mar 2026, 20:30 UTC

Last modified by the source

4 Mar 2026, 18:38 UTC

Source last checked

26 Oct 2026, 14:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-94rc-cqvm-m4pw

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# Patch Next advisory brief: CVE-2026-28695

Advisory: Craft CMS Vulnerable to Authenticated RCE via Twig SSTI - create() function + Symfony Process gadget
IDs: CVE-2026-28695, GHSA-94rc-cqvm-m4pw
Record: https://patchnext.com/advisories/cve-2026-28695 (revision 1, source checked 26 Oct 2026, 14:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: craftcms/cms 5.9.0-beta.1, 4.17.0-beta.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist craftcms/cms: affected >= 5.8.7, < 5.9.0-beta.1; >= 4.0.0-RC1, < 4.17.0-beta.1; fixed in 5.9.0-beta.1, 4.17.0-beta.1

## 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-94rc-cqvm-m4pw (GitHub-reviewed advisory GHSA-94rc-cqvm-m4pw lists affected ranges: Packagist craftcms/cms >=5.8.7 =4.0.0-RC1 <4.17.0-beta.1)

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