جزئیات آسیب‌پذیری

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.

• https://joshua.hu/cjson-json-parser-cve-vulnerabilities exploit
• https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON.c#L3057-L3180 technical-description
• https://www.vulncheck.com/advisories/cjson-cjson-compare-exponential-complexity-denial-of-service third-party-advisory