{"id":"CVE-2026-55876","title":"Helium is a free online student planner for classes, homework, grades, and notes","summary":"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…","severity":"low","cvss":3.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","cwe":["CWE-79"],"vendor":"HeliumEdu","product":"platform","affected":["platform < 2.2.60"],"published":"2026-10-15","updated":"2026-10-15","sourceUpdated":"2026-10-15T18:17:28.307","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55876","references":[{"url":"https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88","label":"security-advisories@github.com"},{"url":"https://github.com/HeliumEdu/platform/security/advisories/GHSA-7r65-76fw-ch5c","label":"security-advisories@github.com"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-15T18:23:58.451Z","slug":"CVE-2026-55876","body":"## Overview\n\nHelium 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":19,"depthScoreParts":{"impact":19.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}