{"id":"CVE-2026-54721","aliases":["GHSA-g8wr-r2v2-vqc6"],"url":"https://o3.security/vulnerability/CVE-2026-54721","summary":"Silverstripe UserForms: Remote code execution via userforms email subject","details":"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.","published":"2026-08-27T16:52:46.023Z","modified":"2026-09-11T03:31:04.130360298Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00415,"percentile":0.34962,"asOf":"2026-09-10"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"silverstripe/userforms","fixedVersion":"6.4.9"},{"ecosystem":"Packagist","name":"silverstripe/userforms","fixedVersion":"7.0.7"},{"ecosystem":"Packagist","name":"silverstripe/userforms","fixedVersion":"7.1.1"}],"fix":{"url":"https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702","label":"silverstripe/silverstripe-userforms@23c0698"},"references":[{"type":"WEB","url":"https://github.com/silverstripe/silverstripe-userforms/releases/tag/6.4.9"},{"type":"WEB","url":"https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.0.7"},{"type":"WEB","url":"https://github.com/silverstripe/silverstripe-userforms/releases/tag/7.1.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54721.json"},{"type":"ADVISORY","url":"https://github.com/silverstripe/silverstripe-userforms/security/advisories/GHSA-g8wr-r2v2-vqc6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54721"},{"type":"FIX","url":"https://github.com/silverstripe/silverstripe-userforms/commit/23c069866900c19b499bfa997d1e251e97491702"},{"type":"FIX","url":"https://github.com/silverstripe/silverstripe-userforms/commit/c55494ad7c717b199a3c1663b43a54db5d95604c"},{"type":"FIX","url":"https://github.com/silverstripe/silverstripe-userforms/pull/1441"},{"type":"FIX","url":"https://github.com/silverstripe/silverstripe-userforms/pull/1442"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/userforms/CVE-2026-54721.yaml"},{"type":"PACKAGE","url":"https://github.com/silverstripe/silverstripe-userforms"},{"type":"WEB","url":"https://www.silverstripe.org/download/security-releases/cve-2026-54721"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-11T03:31:04.130360298Z"}}