{"id":"CVE-2026-55876","revision":null,"records":[{"revision":"0ae47d419f5e4df69d128cdc236889ea","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-55876","aliases":[],"title":"Helium: Stored XSS via Unrestricted SVG File Upload — Authenticated Users Can Store Executable Scripts","description":"Helium is a free online student planner for classes, homework, grades, and notes. Prior to 2.2.60, the POST /planner/attachments/ endpoint allows authenticated users to upload SVG and HTML attachments because conf/configs/common.py omits those formats from BLOCKED_ATTACHMENT_EXTENSIONS and BLOCKED_ATTACHMENT_MIME_TYPES, and helium/planner/serializers/attachmentserializer.py relies on those blocklists. An uploaded SVG served as image/svg+xml can execute embedded script when a visitor opens its public attachment URL, allowing persistent attacker-controlled active content and phishing under an application-managed storage URL. The attachment storage uses a separate origin from the application, so same-origin policy prevents the script from reading application cookies or storage, and application-session compromise is not supported by the maintained deployment configuration. This issue is fixed in version 2.2.60.","state":0,"publishedAt":"2026-10-15T17:23:07.781+00:00","modifiedAt":"2026-10-21T01:01:03.086+00:00","affected":[{"ecosystem":"Vendor product","name":"platform","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"HeliumEdu\",\n                    \"product\": \"platform\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 2.2.60\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","score":3.5,"severity":"LOW"}],"references":["https://github.com/HeliumEdu/platform/security/advisories/GHSA-7r65-76fw-ch5c","https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-55876","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-55876","identifiers":["CVE-2026-55876"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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