CVE-2026-54721
Published:August 27, 2026
Updated:September 24, 2026
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.
Affected Packages
https://github.com/silverstripe/silverstripe-userforms.git (GITHUB):
Affected version(s) >=7.0.0 <7.0.7Fix Suggestion:
Update to version 7.0.7https://github.com/silverstripe/silverstripe-userforms.git (GITHUB):
Affected version(s) =v5.9.2 <6.4.9Fix Suggestion:
Update to version 6.4.9https://github.com/silverstripe/silverstripe-userforms.git (GITHUB):
Affected version(s) =7.1.0 <7.1.1Fix Suggestion:
Update to version 7.1.1silverstripe/userforms (PHP):
Affected version(s) >=7.0.0 <7.0.7Fix Suggestion:
Update to version 7.0.7silverstripe/userforms (PHP):
Affected version(s) >=dev-dependabot/npm_and_yarn/async-2.6.4 <6.4.9Fix Suggestion:
Update to version 6.4.9silverstripe/userforms (PHP):
Affected version(s) =7.1.0 <7.1.1Fix Suggestion:
Update to version 7.1.1silverstripe/userforms (PHP):
Affected version(s) >=7.1.0 <7.1.1Fix Suggestion:
Update to version 7.1.1silverstripe/userforms (PHP):
Affected version(s) =v5.9.2 <6.4.9Fix Suggestion:
Update to version 6.4.9Related Resources (13)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.41