CVE-2026-29036: Davegamble Cjson

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Davegamble Cjson: from 1.5.0, up to and including 1.7.19

Published 2026-08-11. Last modified 2026-09-24.