Vulnerability in Davegamble Cjson
CVE-2026-29036
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (36.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.002
Affected products
- Davegamble Cjson — versions 1.5.0
Weakness classification (CWE)
References
- github.com/DaveGamble/cJSON (product)
- www.vulncheck.com/advisories/cjson-wrong-key-modification-via-json-pointer-esca… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-29036?
- CVE-2026-29036 is a high-severity vulnerability in Davegamble Cjson, classified under Use of Incorrectly-Resolved Name or Reference. CVSS score: 7.5/10. Published 2026-08-11.
- How severe is CVE-2026-29036?
- High severity. CVSS v3 base score is 7.5 out of 10.