Executive brief
libical is a widely used open-source library for handling calendar data (iCalendar files). A vulnerability in this library allows an attacker to send a specially crafted calendar file that can crash applications or potentially allow the attacker to read sensitive information from the computer's memory. This could lead to service outages or the exposure of private data handled by email clients and calendar applications.
Technical details
A use-after-free vulnerability exists in libical (specifically identified in version 2.0 and earlier) within the handling of iCalendar (.ics) files. The flaw is triggered during the parsing of crafted calendar components, specifically involving functions like icalreqstattype_as_string_r and icalvalue_as_ical_string_r. A remote attacker can exploit this by providing a malicious .ics file to an application using the library. Successful exploitation can result in a denial of service (application crash) or an information leak where the attacker can read significant portions of heap memory. The vulnerability was confirmed via AddressSanitizer reports showing a READ of freed memory during string conversion processes.
Affected products
- libical project libical 2.0 and earlier
Timeline
- 2016-12-15: disclosed: Public disclosure on oss-security mailing list
- 2017-01-18: advisory: NVD publication date