CVE-2026-67216
cJSON cJSON_Compare Exponential Complexity Denial of Service
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.
INFO
Published Date :
July 29, 2026, 2:16 p.m.
Last Modified :
July 29, 2026, 4:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update cJSON to a patched version.
- Avoid using cJSON_Compare on deeply nested JSON.
- Validate JSON structure before comparison.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-67216.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-67216 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-67216
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-67216 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-67216 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Jul. 29, 2026
Action Type Old Value New Value Changed Affected [{'vendor': 'DaveGamble', 'product': 'cJSON', 'defaultStatus': 'affected'}] [{'vendor': 'DaveGamble', 'product': 'cJSON', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '1.7.19'}], 'defaultStatus': 'affected'}] -
New CVE Received by [email protected]
Jul. 29, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'DaveGamble', 'product': 'cJSON', 'defaultStatus': 'affected'}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-407 Added Reference https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON.c#L3057-L3180 Added Reference https://joshua.hu/cjson-json-parser-cve-vulnerabilities Added Reference https://www.vulncheck.com/advisories/cjson-cjson-compare-exponential-complexity-denial-of-service