CVE-2026-77399

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.

• CWE-400
• CWE-834

• https://github.com/collective/icalendar/commit/157f85137c65565a308bbcf4fdcc7d8ebce01267
• https://github.com/collective/icalendar/commit/cddd37226adbc52cca52a399f61d38a378221219
• https://github.com/collective/icalendar/pull/1571
• https://github.com/collective/icalendar/releases/tag/v7.2.2
• https://github.com/collective/icalendar/security/advisories/GHSA-qjcq-q7h7-r74v

Published

Sep 22, 2026

Last Modified

Sep 23, 2026

Status

Awaiting Analysis

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-7739A weakness has been identified in justdan96 tsMuxer up to 2.…3.3
• CVE-2026-77391A security flaw has been discovered in SourceCodester Dynami…4.3
• CVE-2026-77392A weakness has been identified in SourceCodester Dynamic Inp…6.3
• CVE-2026-77393In Ignition 8.1.53 and earlier, the Gateway "Create Project …8.8
• CVE-2026-77394OpenC3 COSMOS provides the functionality needed to send comm…7.6
• CVE-2026-77396PJSIP is a free and open source multimedia communication lib…6.9
• CVE-2026-7740A security vulnerability has been detected in justdan96 tsMu…3.3
• CVE-2026-77401Zope AccessControl provides a general security framework for…6.8
• CVE-2026-77403RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13…8.9
• CVE-2026-77404RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13…8.7
• CVE-2026-77405RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13…9.4
• CVE-2026-77406RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13…8.2