CVE-2026-67216

Description

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.

Weakness classification

• disclosure@vulncheck.com: CWE-407

Primary references

• disclosure@vulncheck.com — Patch
• disclosure@vulncheck.com — Exploit, Press/Media Coverage, Third Party Advisory
• disclosure@vulncheck.com — Third Party Advisory