{"id":"UBUNTU-CVE-2026-77399","details":"icalendar is an RFC 5545 compatible parser and generator of iCalendar files for Python. From 6.1.0 until 7.2.2, vInt.from_ical accepts an attacker-controlled VALARM REPEAT value and applications that request alarm times can eagerly expand it without an application-level limit. Alarms.times and Alarms.active reach the unbounded expansion in versions starting with 6.1.0, while Alarm.triggers adds a second affected path starting with 7.0.0. Parsing alone does not trigger the issue, but accessing these properties can consume excessive CPU time and heap memory and terminate or stall a service. This issue is fixed in version 7.2.2.","modified":"2026-09-24T02:00:47.129313948Z","published":"2026-09-22T19:16:00Z","upstream":["CVE-2026-77399"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-77399"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-77399"},{"type":"REPORT","url":"https://github.com/collective/icalendar/commit/157f85137c65565a308bbcf4fdcc7d8ebce01267"},{"type":"REPORT","url":"https://github.com/collective/icalendar/commit/cddd37226adbc52cca52a399f61d38a378221219"},{"type":"REPORT","url":"https://github.com/collective/icalendar/pull/1571"},{"type":"REPORT","url":"https://github.com/collective/icalendar/releases/tag/v7.2.2"},{"type":"REPORT","url":"https://github.com/collective/icalendar/security/advisories/GHSA-qjcq-q7h7-r74v"}],"affected":[{"package":{"name":"python-icalendar","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/python-icalendar?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.8-1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.8-1","binary_name":"python-icalendar"},{"binary_name":"python3-icalendar","binary_version":"3.8-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77399.json"}},{"package":{"name":"python-icalendar","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/python-icalendar?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.8-2","3.11.7-3","4.0.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python-icalendar","binary_version":"4.0.0-1"},{"binary_version":"4.0.0-1","binary_name":"python3-icalendar"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77399.json"}},{"package":{"name":"python-icalendar","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python-icalendar?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.3-3","4.0.3-4"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-icalendar","binary_version":"4.0.3-4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77399.json"}},{"package":{"name":"python-icalendar","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-icalendar?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.3-4"],"ecosystem_specific":{"binaries":[{"binary_version":"4.0.3-4","binary_name":"python3-icalendar"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77399.json"}},{"package":{"name":"python-icalendar","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-icalendar?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.0.7-1","5.0.11-1"],"ecosystem_specific":{"binaries":[{"binary_version":"5.0.11-1","binary_name":"python3-icalendar"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77399.json"}},{"package":{"name":"python-icalendar","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-icalendar?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.0.1-3","6.3.1-1","6.3.1-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-icalendar","binary_version":"6.3.1-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-77399.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}