---
id: CVE-2026-55875
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, any authenticated user can submit an arbitrary URL to
  POST /feed/externalcalendars/, where
  helium/feed/services/icalexternalcalendarservic…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-918
vendor: HeliumEdu
product: platform
affected:
  - platform < 2.2.60
published: '2026-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T18:17:28.130'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55875'
references:
  - url: >-
      https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88
    label: security-advisories@github.com
  - url: >-
      https://github.com/HeliumEdu/platform/security/advisories/GHSA-2f83-94pv-v3f5
    label: security-advisories@github.com
  - url: >-
      https://github.com/HeliumEdu/platform/security/advisories/GHSA-2f83-94pv-v3f5
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-15T17:47:47.971513Z'
ingestedAt: '2026-10-15T18:23:58.451Z'
---

## Overview

Helium is a free online student planner for classes, homework, grades, and notes. Prior to 2.2.60, any authenticated user can submit an arbitrary URL to POST /feed/externalcalendars/, where helium/feed/services/icalexternalcalendarservice.py uses validate_url to check only URL syntax before passing the value to urllib.request.urlopen, and fetch_ical_conditional periodically refetches the stored URL. The server can therefore issue requests to attacker-selected external or internal hosts, while distinct responses, including an uncaught http.client.RemoteDisconnected condition for non-HTTP services, reveal internal host and port reachability. The supported impact is forced outbound requests and internal service reconnaissance; the advisory does not demonstrate secret retrieval because the relevant ECS credentials path is task-specific and unpredictable. This issue is fixed in version 2.2.60.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.