High severity · published Aug 11, 2026
CVE-2026-29036
cJSON 1.7.19 Wrong-Key Modification via JSON Pointer Escape Decoding
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
cJSON versions 1.5.0 through 1.7.19 contain an incorrectly-resolved name or reference vulnerability in the decode_pointer_inplace() function within cJSON_Utils.c that allows unauthenticated attackers to cause JSON Patch operations to target wrong object keys by supplying crafted JSON Pointer escape sequences (~0 or ~1) in patch paths. Attackers can submit malicious RFC 6902 JSON Patch input to applications using cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive() to silently corrupt data or delete unintended keys, potentially bypassing authorization controls in applications that rely on JSON Patch for access-controlled data modification.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CJ
cJSON · DaveGamble
1.5.0 through 1.7.19 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-29036
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-29036
github.com
https://github.com/DaveGamble/cJSON
www.vulncheck.com
https://www.vulncheck.com/advisories/cjson-wrong-key-modification-via-json-pointer-escape-decoding
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