---
id: CVE-2026-54721
title: Silverstripe UserForms provides a visual form builder for the Silverstripe CMS
summary: >-
  Silverstripe UserForms provides a visual form builder for the Silverstripe
  CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient
  subject field in the CMS accepts a specially crafted payload that can be
  interpreted a…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-94
  - CWE-20
vendor: silverstripe
product: silverstripe/userforms
affected:
  - silverstripe/userforms < 6.4.9
  - 'silverstripe/userforms >= 7.0.0, < 7.0.7'
  - 'silverstripe/userforms >= 7.1.0, < 7.1.1'
patched:
  - silverstripe/userforms 6.4.9
  - silverstripe/userforms 7.0.7
  - silverstripe/userforms 7.1.1
published: '2026-08-27'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:09:13.080'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-54721'
references:
  - url: >-
      https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702
    label: security-advisories@github.com
  - url: >-
      https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c
    label: security-advisories@github.com
  - url: 'https://github.com/silverstripe/silverstripe-userforms/pull/1441'
    label: security-advisories@github.com
  - url: 'https://github.com/silverstripe/silverstripe-userforms/pull/1442'
    label: security-advisories@github.com
  - url: 'https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9'
    label: security-advisories@github.com
  - url: 'https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7'
    label: security-advisories@github.com
  - url: 'https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1'
    label: security-advisories@github.com
  - url: >-
      https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6
    label: security-advisories@github.com
  - url: >-
      https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/userforms/CVE-2026-54721.yaml
  - url: 'https://www.silverstripe.org/download/security-releases/cve-2026-54721'
  - url: 'https://github.com/advisories/GHSA-g8wr-r2v2-vqc6'
tags:
  - nvd
  - ghsa
  - composer
epss: 0.00733
epssPercentile: 0.52414
aliases:
  - GHSA-g8wr-r2v2-vqc6
ecosystem: composer
ingestedAt: '2026-08-27T17:05:19.997Z'
---

## Overview

Silverstripe UserForms provides a visual form builder for the Silverstripe CMS. From 6.0.0 until 6.4.9, 7.0.7, and 7.1.1, the userform email recipient subject field in the CMS accepts a specially crafted payload that can be interpreted as executable server-side code. An authenticated CMS user with permission to configure a UserForms email recipient can use the subject field to run arbitrary code on the server, compromising confidentiality, integrity, and availability. This issue is fixed in versions 6.4.9, 7.0.7, and 7.1.1.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-54721)

Affected packages:

- `silverstripe/userforms < 6.4.9`
- `silverstripe/userforms >= 7.0.0, < 7.0.7`
- `silverstripe/userforms >= 7.1.0, < 7.1.1`

Patched in:

- `silverstripe/userforms 6.4.9`
- `silverstripe/userforms 7.0.7`
- `silverstripe/userforms 7.1.1`

Source: https://github.com/advisories/GHSA-g8wr-r2v2-vqc6