Reference Vulnerability in cJSON Library Affecting Numerous Applications
CVE-2026-29036

8.7HIGH

Key Information:

Vendor

Davegamble

Status
Cjson
Vendor
CVE Published:
11 August 2026

What is CVE-2026-29036?

The cJSON library versions 1.5.0 through 1.7.19 are vulnerable to an incorrectly-resolved name or reference issue in the decode_pointer_inplace() function located within cJSON_Utils.c. This vulnerability can be exploited by unauthenticated attackers who supply specially crafted JSON Pointer escape sequences (~0 or ~1) in JSON Patch operations. As a result, attackers may manipulate the keys of JSON objects, potentially corrupting data or deleting unintended object keys. Such actions can lead to unauthorized modifications of data, especially in applications that rely on cJSONUtils_ApplyPatches() and cJSONUtils_ApplyPatchesCaseSensitive() for JSON Patch operations, thus bypassing critical authorization controls.

Affected Version(s)

cJSON 1.5.0 <= 1.7.19

References

https://github.com/DaveGamble/cJSON
product
https://www.vulncheck.com/advisories/cjson-wrong-key-modi...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Kazuma Matsumoto, a security researcher at GMO Cybersecurity by IERAE, Inc.
.