Answer in brief
CVE-2026-54721 records a High severity (CVSS 8.8) vulnerability in Silverstripe UserForms: Remote code execution via userforms email subject. The current sources do not mark it as known exploited. The current feed maps silverstripe/userforms (composer), silverstripe/userforms (composer), silverstripe/userforms (composer), silverstripe/silverstripe-userforms (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps silverstripe/userforms (composer), silverstripe/userforms (composer), silverstripe/userforms (composer), silverstripe/silverstripe-userforms (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| silverstripe/userformscomposer | <6.4.9 | 6.4.9 |
| silverstripe/userformscomposer | >=7.0.0,<7.0.7 | 7.0.7 |
| silverstripe/userformscomposer | >=7.1.0,<7.1.1 | 7.1.1 |
| silverstripe/silverstripe-userformsgeneric | < 6.4.9 || >= 7.0.0, < 7.0.7 || >= 7.1.0, < 7.1.1 | Not reported |
Published upstream
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 27, 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.
Quoted source text, attributed separately from HOL analysis.