CVE-2026-67216

cJSON cJSON_Compare Exponential Complexity Denial of Service

Published Jul 29, 2026 CVSS 4.0 · 8.2 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values 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.
Title cJSON cJSON_Compare Exponential Complexity Denial of Service
First Time appeared Davegamble
Davegamble cjson
Weaknesses CWE-407
CPEs cpe:2.3:a:davegamble:cjson:*:*:*:*:*:*:*:*
Vendors & Products Davegamble
Davegamble cjson
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.2, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Jul 30, 2026, 3:19 PM
Reserved
Jul 28, 2026, 7:20 PM
Status
Analyzed
Published
Jul 29, 2026, 2:16 PM
Modified
Oct 23, 2026, 11:10 PM
Severity
Moderate
Public date
Jul 29, 2026, 1:32 PM