Use After Free Vulnerability in cJSON by DaveGamble
CVE-2026-87933

6.9MEDIUM

Key Information:

Vendor

Davegamble

Status
Cjson
Vendor
CVE Published:
10 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-87933?

A significant vulnerability has been identified in cJSON, specifically within the function cJSONUtils_MergePatch in the file cJSON_Utils.c. This flaw can lead to a use after free condition, which allows attackers to exploit the issue remotely. Once this vulnerability is triggered, it can potentially enable unauthorized actions within the system. The issue has been made publicly known, and a pull request to address it is currently pending acceptance. Maintaining updated software is crucial to mitigating risks associated with this vulnerability.

Affected Version(s)

cJSON 1.7.0

cJSON 1.7.1

cJSON 1.7.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-87933 - Proof of Concept

References

https://vuldb.com/vuln/401815
vdb-entrytechnical-description
https://vuldb.com/vuln/401815/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-87933
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

lrrh (VulDB User)
VulDB CNA Team
.