# CVE-2026-33157: Craft CMS: Potential authenticated Remote Code Execution via malicious attached Behavior

> Authenticated users can execute arbitrary code via unsanitized field layout parameters in Craft CMS control panel.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Mar 2026
- **Updated:** 25 Mar 2026
- **Also known as:** CLSA-2026-1790174106, GHSA-2fph-6v5w-89hh

## What is CVE-2026-33157?

CVE-2026-33157 is a high-severity code injection vulnerability in Craftcms Craft Cms, published on 24 Mar 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). From version 5.6.0 to before version 5.9.13, a Remote Code Execution (RCE) vulnerability exists in Craft CMS, it can be exploited by any authenticated user with control panel access. This is a bypass of a previous fix. The existing patches add cleanseConfig() to assembleLayoutFromPost() and various FieldsController actions to strip Yii2 behavior/event injection keys ("as" and "on" prefixed keys). However, the fieldLayouts parameter in ElementIndexesController::actionFilterHud() is passed directly to FieldLayout::createFromConfig() without any sanitization, enabling the same behavior injection attack chain. This issue has been patched in version 5.9.13.

Weakness: CWE-470 (Use of Externally-Controlled Input to Select Classes or Code)

## Which versions are affected by CVE-2026-33157?

2 open source packages ship an affected version, including craftcms/cms. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `craftcms/cms` | Packagist | From 5.6.0 | 5.9.13 |
| `craftcms/cms` | Packagist | From 5.6.0 | 5.9.13 |

Products: Craftcms Craft Cms.

## How do I fix CVE-2026-33157?

Upgrade craftcms/cms to 5.9.13 or later.

## Is CVE-2026-33157 being exploited?

There is no known exploitation of CVE-2026-33157 in the wild and no public exploit code.

Public exploit code:

- Craft CMS CVE-2026-33157 filter-hud behavior-injection RCE PoC (github_poc): https://github.com/TRX-0/CVE-2026-33157-craftcms-rce

## Other vulnerabilities in Craftcms Craft Cms

- [CVE-2025-32432](https://insights.sbomify.com/CVE-2025-32432/): Craft CMS Code Injection (critical 10.0, exploited in the wild)
- [CVE-2024-56145](https://insights.sbomify.com/CVE-2024-56145/): Craft CMS Code Injection (critical 9.3, exploited in the wild)
- [CVE-2025-23209](https://insights.sbomify.com/CVE-2025-23209/): Craft CMS Code Injection (high 8.1, exploited in the wild)
- [CVE-2025-35939](https://insights.sbomify.com/CVE-2025-35939/): Craft CMS External Control of Assumed-Immutable Web Parameter (medium 6.9, exploited in the wild)
- [CVE-2023-41892](https://insights.sbomify.com/CVE-2023-41892/): Craft CMS Remote Code Execution vulnerability (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33157 and fix it if it is affected.

What it is: CVE-2026-33157 is a high-severity code injection vulnerability in Craftcms Craft Cms, published on 24 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-33157 in the wild and no public exploit code.

Affected packages and fixed versions:
- craftcms/cms (Packagist): affected from 5.6.0; fixed in 5.9.13
- craftcms/cms (Packagist): affected from 5.6.0; fixed in 5.9.13

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-2026-33157/ (Markdown: https://insights.sbomify.com/CVE-2026-33157/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33157
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33157
- OSV: https://osv.dev/vulnerability/CVE-2026-33157

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33157/
Summaries are generated and may contain mistakes; the official description above is the record.