CVE-2026-23737
📋 TL;DR
CVE-2026-23737 is a deserialization vulnerability in seroval library versions 1.4.0 and below that allows arbitrary JavaScript code execution. Attackers can exploit this by sending specially crafted JSON data to the fromJSON or fromCrossJSON functions, potentially leading to remote code execution. This affects applications using seroval for client-to-server data transmission.
💻 Affected Systems
- seroval
📦 What is this software?
Seroval by Lxsmnsyc
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through remote code execution, allowing attackers to execute arbitrary commands, steal data, or pivot to other systems.
Likely Case
Data exfiltration, application compromise, or denial of service through malicious code execution in the application context.
If Mitigated
Limited impact with proper input validation and network segmentation, potentially only affecting isolated application components.
🎯 Exploit Status
Exploitation requires 4 separate requests and partial knowledge of serialized data usage patterns.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.4.0
Vendor Advisory: https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-3rxj-6cgf-8cfw
Restart Required: No
Instructions:
1. Update seroval to version 1.4.0 or higher using npm update seroval. 2. Verify the update with npm list seroval. 3. Test application functionality after update.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation for JSON data before passing to seroval functions
Function Restriction
allDisable or restrict usage of fromJSON and fromCrossJSON functions with untrusted input
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all JSON data processed by seroval
- Network segmentation to isolate affected applications and limit blast radius
🔍 How to Verify
Check if Vulnerable:
Check package.json or run npm list seroval to verify version is 1.4.0 or belowCheck Version:
npm list seroval | grep serovalVerify Fix Applied:
Confirm seroval version is 1.4.0 or higher using npm list seroval📡 Detection & Monitoring
Log Indicators:
- Multiple rapid calls to fromJSON/fromCrossJSON functions
- Unusual error patterns in deserialization logs
- Unexpected process spawns from application
Network Indicators:
- Multiple JSON payloads sent to same endpoint in quick succession
- Unusual data patterns in JSON transmissions
SIEM Query:
source="application_logs" AND (message="*fromJSON*" OR message="*fromCrossJSON*") AND count > 4 within 60s