{"schema":"threatline.record/2","record":{"id":"CVE-2026-55876","aliases":["GHSA-7r65-76fw-ch5c"],"summary":"Helium: Stored XSS via Unrestricted SVG File Upload — Authenticated Users Can Store Executable Scripts","details":"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.","categories":["Unclassified"],"product":"platform","vendor":"HeliumEdu","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-55876","source_modified_at":"2026-10-21T01:01:03.086Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"platform","vendor":"HeliumEdu","versions":[{"version":"< 2.2.60","status":"affected"}],"defaultStatus":null}],"fixed_versions":[],"cvss":3.5,"severity":"Low","kev":{"listed":false},"epss":{"probability":0.00152,"percentile":0.04053,"score_date":"2026-10-23"},"published_at":"2026-10-15T17:23:07.781Z","modified_at":"2026-10-21T01:01:03.086Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-55876","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T01:01:03.086Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-55876","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/HeliumEdu/platform/security/advisories/GHSA-7r65-76fw-ch5c","tags":["exploit"]},{"source":"CVE List","url":"https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88","tags":["x_refsource_MISC"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"poc","automatable":"no","technical_impact":"partial","assessed_at":"2026-10-21T01:00:34.594595Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-21T01:01:03.086Z","content_hash":"e9ab5e71b12d57a3ea5afc9f062edd41161983ab846618492936b001dc33294a"}}