CVE-2026-1848
📋 TL;DR
This vulnerability in MongoDB allows connections from proxy ports to bypass connection counting, potentially causing server crashes when connection limits are exceeded. It affects MongoDB servers with proxy protocol enabled, specifically impacting connections pending proxy protocol header validation.
💻 Affected Systems
- MongoDB
📦 What is this software?
Mongodb by Mongodb
Mongodb by Mongodb
Mongodb by Mongodb
⚠️ Risk & Real-World Impact
Worst Case
Denial of service through server crashes, potentially leading to extended downtime and data unavailability.
Likely Case
Intermittent service disruptions or performance degradation when connection limits are approached.
If Mitigated
Minimal impact with proper connection limits and monitoring in place.
🎯 Exploit Status
Exploitation requires sending connections to proxy port but no authentication or special payload needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check MongoDB security advisories for specific fixed versions
Vendor Advisory: https://jira.mongodb.org/browse/SERVER-114695
Restart Required: Yes
Instructions:
1. Check MongoDB security advisory for fixed version. 2. Backup databases. 3. Upgrade MongoDB to patched version. 4. Restart MongoDB service.
🔧 Temporary Workarounds
Disable Proxy Protocol
allDisable proxy protocol support if not required for your deployment
Modify MongoDB configuration to remove proxyProtocol parameter
Reduce Connection Limits
allLower maximum connection limits to reduce impact window
Set net.maxIncomingConnections to conservative value in mongod.conf
🧯 If You Can't Patch
- Implement network controls to restrict access to MongoDB proxy ports
- Deploy rate limiting or connection throttling at network perimeter
🔍 How to Verify
Check if Vulnerable:
Check if proxy protocol is enabled in MongoDB configuration and version matches affected rangeCheck Version:
mongod --versionVerify Fix Applied:
Verify MongoDB version is updated to patched version and proxy protocol connections are properly counted📡 Detection & Monitoring
Log Indicators:
- Unexpected server restarts
- Connection limit warnings
- Proxy port connection spikes
Network Indicators:
- High volume of connections to MongoDB proxy port
- Connection attempts bypassing normal authentication
SIEM Query:
source="mongodb.log" AND ("restarting" OR "connection limit" OR "proxy")