{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55876","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-06-17T16:59:42.759Z","datePublished":"2026-10-15T17:23:07.781Z","dateUpdated":"2026-10-21T01:01:03.086Z"},"containers":{"cna":{"title":"Helium: Stored XSS via Unrestricted SVG File Upload — Authenticated Users Can Store Executable Scripts","problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":3.5,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/HeliumEdu/platform/security/advisories/GHSA-7r65-76fw-ch5c","tags":["x_refsource_CONFIRM"],"url":"https://github.com/HeliumEdu/platform/security/advisories/GHSA-7r65-76fw-ch5c"},{"name":"https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88","tags":["x_refsource_MISC"],"url":"https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88"}],"affected":[{"vendor":"HeliumEdu","product":"platform","versions":[{"version":"< 2.2.60","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-10-15T17:23:07.781Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-7r65-76fw-ch5c","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/HeliumEdu/platform/security/advisories/GHSA-7r65-76fw-ch5c","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-21T01:00:34.594595Z","id":"CVE-2026-55876","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-10-21T01:01:03.086Z"}}]}}