CVE-2016-5825 Libical Project CVE debrief

Who should care

Administrators and developers who ship or embed libical 0.47 or 1.0, especially applications that parse untrusted calendar files or otherwise accept ICS content from users, mail gateways, sync services, or import workflows.

Technical summary

The NVD record describes an out-of-bounds heap read in icalparser_parse_string when processing a crafted .ics file. The affected CPE criteria enumerate libical_project:libical versions 0.47 and 1.0. NVD assigns CWE-125 and a CVSS 3.0 vector of CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H, which indicates availability impact with required user interaction. The source description also uses remote-attacker wording, so the access pattern should be interpreted using the full NVD record rather than the short summary alone.

Defensive priority

Medium. This is a denial-of-service issue rather than a code-execution flaw, but it affects parsing of potentially untrusted calendar input and can still disrupt services or clients that process ICS data.

Recommended defensive actions

• Inventory systems and applications that include libical and confirm whether they use versions 0.47 or 1.0.
• Upgrade to a fixed libical release if one is available in your software distribution or vendor package stream.
• Restrict or validate untrusted ICS input before parsing, especially in services that import calendar data automatically.
• Monitor application logs and crash reports for parser failures tied to crafted calendar files.
• If upgrading is not immediately possible, reduce exposure by limiting who can submit or synchronize calendar content.

Evidence notes

Source corpus indicates the CVE was published on 2017-01-27. Supporting references include an oss-security mailing list post dated 2016-06-25, a SecurityFocus BID entry, and a Mozilla bug tracker entry. NVD lists affected versions 0.47 and 1.0 and classifies the weakness as CWE-125 with CVSS 3.0 vector AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

Official resources