Jansson, possibly 2.4 and earlier, does not restrict the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via a crafted JSON document.
{ "binaries": [ { "binary_version": "2.5-2ubuntu0.1", "binary_name": "libjansson-dev" }, { "binary_version": "2.5-2ubuntu0.1", "binary_name": "libjansson4" } ], "availability": "No subscription required" }