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CVE-2026-67216highCWE-407

cJSON cJSON_Compare Exponential Complexity Denial of Service

41Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 8.2epss 0.3%
exploitation probability
0.3%top 76% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
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.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
DaveGamble · cJSON
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