CVE-2026-1436
📋 TL;DR
This CVE describes an Insecure Direct Object Reference (IDOR) vulnerability in Graylog API version 2.2.3 where authenticated users can modify user IDs in API URLs to access other users' profiles without authorization. This allows attackers to enumerate valid users and access sensitive personal information including names, email addresses, and activity data. All organizations running the affected Graylog version are vulnerable if they have multiple user accounts.
💻 Affected Systems
- Graylog
📦 What is this software?
Graylog by Graylog
⚠️ Risk & Real-World Impact
Worst Case
Attackers could enumerate all users, access sensitive personal information, potentially leading to identity theft, credential stuffing attacks, or social engineering campaigns against organization members.
Likely Case
Authenticated users accessing other users' profile information, leading to privacy violations and potential credential harvesting for lateral movement.
If Mitigated
Limited to authenticated users only, with no privilege escalation or system compromise beyond information disclosure.
🎯 Exploit Status
Exploitation requires authenticated access but is trivial - simply modify the user ID parameter in API requests. No special tools or skills needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.2.4 or later
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-graylog
Restart Required: Yes
Instructions:
1. Backup Graylog configuration and data. 2. Download Graylog 2.2.4 or later from official repository. 3. Stop Graylog service. 4. Install updated version. 5. Restart Graylog service. 6. Verify functionality.
🔧 Temporary Workarounds
API Access Restriction
linuxRestrict access to the vulnerable API endpoint using network controls or web application firewall rules.
iptables -A INPUT -p tcp --dport 12900 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 12900 -j DROP
User Session Validation
allImplement additional session validation middleware to verify user authorization for requested resources.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Graylog API from untrusted networks.
- Enable detailed audit logging for all user profile access attempts and monitor for suspicious patterns.
🔍 How to Verify
Check if Vulnerable:
As authenticated user, attempt to access /users/{other_user_id} endpoint with different user IDs. If successful, system is vulnerable.Check Version:
grep -i version /etc/graylog/server/server.conf or check Graylog web interface About pageVerify Fix Applied:
After patching, repeat the test - accessing other users' profiles should return authorization errors.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authorization attempts for user profile access
- User accessing profiles with IDs not matching their session
- Unusual pattern of sequential user ID requests
Network Indicators:
- Burst of requests to /users/ endpoint with incrementing IDs
- API requests with user IDs outside expected range
SIEM Query:
source="graylog" AND (uri_path="/users/*" AND user_id!=session_user_id)