CVE-2026-67216

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

• cjson (bug https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1143048) https://joshua.hu/cjson-json-parser-cve-vulnerabilities