CVE-2025-57052
📋 TL;DR
cJSON versions 1.5.0 through 1.7.18 contain an out-of-bounds access vulnerability in the decode_array_index_from_pointer function. This allows remote attackers to bypass array bounds checking and access restricted memory by sending malformed JSON pointer strings containing alphanumeric characters. Any application using vulnerable cJSON versions to parse untrusted JSON data is affected.
💻 Affected Systems
- cJSON
📦 What is this software?
Cjson by Davegamble
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data exfiltration, or service disruption.
Likely Case
Memory corruption leading to denial of service, information disclosure, or application crashes.
If Mitigated
Limited impact if input validation or sandboxing prevents exploitation, though risk remains.
🎯 Exploit Status
Public proof-of-concept exists; exploitation requires sending malformed JSON pointer strings.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.7.19 or later
Vendor Advisory: https://lists.debian.org/debian-lts-announce/2025/09/msg00019.html
Restart Required: Yes
Instructions:
1. Update cJSON to version 1.7.19 or later. 2. Recompile and redeploy any applications using cJSON. 3. Restart affected services.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation to reject malformed JSON pointer strings before processing.
Memory Sanitization
allUse address sanitizers or memory protection mechanisms to detect and prevent out-of-bounds access.
🧯 If You Can't Patch
- Isolate vulnerable systems behind firewalls and restrict network access.
- Implement network-based intrusion detection to monitor for exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Check cJSON version in use; if between 1.5.0 and 1.7.18 inclusive, it is vulnerable.Check Version:
Check application dependencies or use package manager (e.g., 'dpkg -l | grep cjson' on Debian).Verify Fix Applied:
Verify cJSON version is 1.7.19 or later and test with known malicious JSON pointer strings.📡 Detection & Monitoring
Log Indicators:
- Application crashes, memory access errors, or unexpected termination logs.
Network Indicators:
- Incoming JSON payloads containing malformed pointer strings with alphanumeric characters.
SIEM Query:
Search for network traffic containing patterns like '/~' or unusual JSON pointer syntax in payloads.