system
Describe <CVE-2013-1864>.
user
What is <CVE-2013-1864>?
assistant
The Portable Tool Library (aka PTLib) before 2.10.10, as used in Ekiga before 4.0.1, does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted PXML document containing a large number of nested entity references, aka a "billion laughs attack.".