CVE-2026-67215
cJSON through 1.7.19 is vulnerable to uncontrolled recursion leading to stack exhaustion when an untrusted RFC 6902 JSON Patch is applied via cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive().
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
cJSON through 1.7.19 is vulnerable to uncontrolled recursion leading to stack exhaustion when an untrusted RFC 6902 JSON Patch is applied via cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive(). A patch containing add and copy operations grafts duplicated subtrees to amplify document depth beyond the parser's nesting limit: cJSON_Delete() recurses with no depth bound, and the cJSON_Duplicate() guard CJSON_CIRCULAR_LIMIT is set to 10000, ten times the parser's 1000-level nesting limit and high enough to overflow a default thread stack. An attacker who can supply the patch document can crash the process, resulting in denial of service.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.46% probability · 39th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-674
- Affected
- davegamble/cjson
- Source
- disclosure@vulncheck.com
References
- https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON.c#L253-L261Patch
- https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON_Utils.c#L906-L940Patch
- https://joshua.hu/cjson-json-parser-cve-vulnerabilitiesExploit, Press/Media Coverage, Third Party Advisory
- https://www.vulncheck.com/advisories/cjson-json-patch-copy-add-uncontrolled-recursion-stack-exhaustionThird Party Advisory
- https://joshua.hu/cjson-json-parser-cve-vulnerabilitiesExploit, Press/Media Coverage, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.