cJSON 1.7.15 might allow a denial of service via a crafted JSON document such as {"a": true, "b": [ null,9999999999999999999999999999999999999999999999912345678901234567]}.
Exploitability
AV:LAC:HPR:NUI:NScope
S:UImpact
C:NI:NA:L2.9/CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:LOther