In SilverStripe through 4.6.0-rc1, a FormField with square brackets in the field name skips validation.
https://www.silverstripe.org/download/security-releases/cve-2020-26138
https://www.silverstripe.org/download/security-releases/
https://www.silverstripe.org/blog/tag/release
https://forum.silverstripe.org/c/releases
Source: Mitre, NVD
Published: 2021-06-08
Updated: 2026-06-17
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.00292