silverstripe/userforms vulnerable to remote code execution via userforms email subject
Impact
The userform email subject field in the CMS is vulnerable to a specially crafted payload being used to run arbitrary code on the server.
Reported by
Jack Wallace from Bastion Security
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | silverstripe/userforms | < 6.4.9, >= 7.0.0, < 7.0.7, >= 7.1.0, < 7.1.1 | 6.4.9, 7.0.7, 7.1.1 |
References
- https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6
- https://github.com/silverstripe/silverstripe-userforms/pull/1441
- https://github.com/silverstripe/silverstripe-userforms/pull/1442
- https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702
- https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c
- https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/userforms/CVE-2026-54721.yaml
- https://github.com/silverstripe/silverstripe-userforms
- https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9
- https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7
- https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1
- https://www.silverstripe.org/download/security-releases/cve-2026-54721
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-20, CWE-94- Platform
- Composer
- Package
silverstripe/userforms- Disclosed
- 27.08.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-g8wr-r2v2-vqc6 - CC BY 4.0
Vulnerability history: silverstripe/userforms
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 05.2022 08.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 1
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 1
-
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