What’s Vulnerable › Vulnerabilities

CVE-2026-67217: cJSON JSON Patch Non-Atomic Application Destroys Data Before Validation

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-29 · updated 2026-10-23
• Weakness: CWE-696

Description

cJSON through 1.7.19 applies RFC 6902 JSON Patch operations non-atomically in apply_patch() in cJSON_Utils.c. For a replace operation that is missing its value member, or a move operation whose destination path cannot be resolved, the existing target member is detached and deleted before the operation is fully validated, so the target document is mutated while cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive() returns a failure status. An attacker who can supply the patch document can destroy addressable members of the target document even though the API reports that the patch failed, defeating the all-or-nothing behavior callers rely on to reject bad patches.

Affected products

• DaveGamble cJSON: through 1.7.19

References

• https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON_Utils.c#L887-L948
• https://joshua.hu/cjson-json-parser-cve-vulnerabilities
• https://www.vulncheck.com/advisories/cjson-json-patch-non-atomic-application-destroys-data-before-validation
• https://joshua.hu/cjson-json-parser-cve-vulnerabilities

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