The CVSS 7.5 score for CVE-2026-67216 obscures a more serious reality. cJSON_Compare() performs bidirectional recursive comparison — it traverses each shared subtree twice during equality checking, yielding O(2^n) time complexity where n is nesting depth. This is not a memory corruption bug; it's an algorithmic complexity flaw that standard security tooling cannot detect. Static analyzers, ASAN, and fuzz harnesses will pass this code green because the vulnerability manifests only as exponential CPU consumption under adversarial input, not as a crash or memory error.
The practical attack cost is negligible. Approximately 40 levels of nested JSON — a few hundred bytes — triggers the exponential behavior. A single request can saturate a thread for hours. The asymmetry is stark: attacker sends a tweet-sized payload, defender pays exponential CPU time, and because the comparison must complete or timeout, one request can consume an entire request-handling thread. In threaded or connection-pool-limited servers, enough saturated threads trigger queuing, cascading timeouts, and retry storms across upstream dependencies.
The critical unknown is reachability. cJSON_Compare() is a comparison utility, not a parser — downstream code must explicitly invoke it on data derived from untrusted sources. Examine your codebase for calls to cJSON_Compare() on JSON that originated from external input. Likely vectors include JSON diff tools, caching layers that compare cached versus incoming payloads, API contract validators, and test harnesses that compare expected versus actual responses. If any of these run in request paths, you have a trivially weaponizable DoS vector.
The scoring limitation is real: CVSS was designed around memory-safety vulnerabilities and cannot represent algorithmic asymmetry. The defender's cost does not scale proportionally with attacker cost — it scales exponentially. Treat this as a high-severity DoS risk in any code path where untrusted JSON reaches cJSON_Compare(), regardless of the CVE's 7.5 score.