CVE-2026-23736
📋 TL;DR
CVE-2026-23736 is a prototype pollution vulnerability in seroval's JSON deserialization functionality that allows attackers to modify JavaScript object prototypes by crafting malicious object keys. This affects applications using seroval versions 1.4.0 and below for JSON deserialization. Successful exploitation could lead to denial of service, data corruption, or potentially remote code execution depending on the application context.
💻 Affected Systems
- seroval
📦 What is this software?
Seroval by Lxsmnsyc
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution through prototype pollution leading to complete system compromise, data theft, or service disruption.
Likely Case
Denial of service, application crashes, or data corruption through prototype pollution affecting application stability.
If Mitigated
Limited impact with proper input validation and sandboxing, potentially causing only minor application errors.
🎯 Exploit Status
Proof of concept available in GitHub advisory; exploitation requires attacker to control JSON input to deserialization.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.4.1
Vendor Advisory: https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-hj76-42vx-jwp4
Restart Required: No
Instructions:
1. Update seroval package to version 1.4.1 or higher. 2. For npm: 'npm update seroval'. 3. For yarn: 'yarn upgrade seroval'. 4. Verify update with 'npm list seroval' or 'yarn list seroval'.
🔧 Temporary Workarounds
Input validation wrapper
allImplement custom input validation before passing data to seroval deserialization
// JavaScript example: Validate object keys before deserialization
function safeDeserialize(input) {
// Add key validation logic here
return seroval.deserialize(input);
}
🧯 If You Can't Patch
- Disable or restrict JSON deserialization functionality in seroval
- Implement strict input validation and sanitization for all JSON inputs
🔍 How to Verify
Check if Vulnerable:
Check package.json or lock file for seroval version <=1.4.0Check Version:
npm list seroval | grep seroval || yarn list seroval | grep serovalVerify Fix Applied:
Verify seroval version is >=1.4.1 using package manager commands📡 Detection & Monitoring
Log Indicators:
- Unusual JSON parsing errors
- Application crashes during deserialization
- Unexpected prototype modifications
Network Indicators:
- Malformed JSON payloads with unusual object keys
- Requests containing __proto__ or constructor properties
SIEM Query:
source="application_logs" AND ("seroval" OR "deserialize") AND ("error" OR "crash" OR "prototype")