{"id":"CVE-2026-55875","aliases":["EUVD-2026-102222","GHSA-2f83-94pv-v3f5"],"status":"published","title":"Helium: SSRF via External Calendar URL Allows Authenticated Users to Probe Internal Network","description":"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.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0021,"percentile":0.11309,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-918"],"published":"2026-10-15T17:24:00Z","modified":"2026-10-28T02:31:08Z","products":[{"vendor":"heliumedu","product":"platform"},{"vendor":"runzero","product":"platform"}],"references":[{"url":"https://github.com/HeliumEdu/platform/security/advisories/GHSA-2f83-94pv-v3f5","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/HeliumEdu/platform/commit/f0de5c985c701942758b805a3d11dfb008a6af88","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55875.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55875","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-55875","title":"Helium: SSRF via External Calendar URL Allows Authenticated Users to Probe Internal Network","description":"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.","status":"published","published":"2026-10-15T17:24:00.931Z","modified":"2026-10-15T17:48:20.682Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:20:11.925815Z"}],"euvd":[{"id":"EUVD-2026-102222","description":"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.","status":"published","published":"2026-10-15T17:24:00Z","modified":"2026-10-15T17:48:20Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T17:00:11.403253Z"}],"nvd":[{"id":"CVE-2026-55875","description":"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.","status":"published","published":"2026-10-15T18:17:28.13Z","modified":"2026-10-16T20:04:29.76Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:59.751798Z"}],"osv":[{"id":"CVE-2026-55875","title":"Helium: SSRF via External Calendar URL Allows Authenticated Users to Probe Internal Network","description":"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.","status":"published","published":"2026-10-15T17:24:00.931Z","modified":"2026-10-28T02:31:08.107965641Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:45:11.609219Z"}]}}