What’s Vulnerable › Vulnerabilities

CVE-2026-67215: cJSON JSON Patch copy/add Uncontrolled Recursion Stack Exhaustion

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-29 · updated 2026-10-23
• Weakness: CWE-674

Description

cJSON through 1.7.19 is vulnerable to uncontrolled recursion leading to stack exhaustion when an untrusted RFC 6902 JSON Patch is applied via cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive(). A patch containing add and copy operations grafts duplicated subtrees to amplify document depth beyond the parser's nesting limit: cJSON_Delete() recurses with no depth bound, and the cJSON_Duplicate() guard CJSON_CIRCULAR_LIMIT is set to 10000, ten times the parser's 1000-level nesting limit and high enough to overflow a default thread stack. An attacker who can supply the patch document can crash the process, resulting in denial of service.

Affected products

• DaveGamble cJSON: through 1.7.19

References

• https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON.c#L253-L261
• https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON_Utils.c#L906-L940
• https://joshua.hu/cjson-json-parser-cve-vulnerabilities
• https://www.vulncheck.com/advisories/cjson-json-patch-copy-add-uncontrolled-recursion-stack-exhaustion
• https://joshua.hu/cjson-json-parser-cve-vulnerabilities

Get alerted when CVE-2026-67215 or the next vulnerability affects your stack