CVE-2026-1440
📋 TL;DR
A reflected Cross-Site Scripting (XSS) vulnerability in Graylog Web Interface version 2.2.3 allows attackers to inject malicious JavaScript via specially crafted URLs. When users visit these URLs, arbitrary code executes in their browser, potentially compromising their session. This affects Graylog administrators and users accessing the web console.
💻 Affected Systems
- Graylog
📦 What is this software?
Graylog by Graylog
⚠️ Risk & Real-World Impact
Worst Case
Attacker steals administrator session cookies, gains full administrative access to Graylog, manipulates log data, or deploys backdoors in the logging infrastructure.
Likely Case
Attacker performs session hijacking of regular users, steals authentication tokens, or redirects users to malicious sites.
If Mitigated
With proper input validation and output encoding, no code execution occurs; malicious payloads are rendered as harmless text.
🎯 Exploit Status
Exploitation requires user interaction (clicking a malicious link), but crafting the payload is straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.0 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 and install Graylog version 2.3.0 or later from the official repository. 3. Restart Graylog services. 4. Verify the fix by testing the vulnerable endpoint.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rule
allDeploy a WAF rule to block malicious XSS payloads targeting the '/system/pipelines/' endpoint.
Input Validation Filter
allImplement a reverse proxy or middleware to sanitize URL parameters before they reach Graylog.
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to block inline script execution.
- Restrict access to Graylog web interface to trusted IP addresses only.
🔍 How to Verify
Check if Vulnerable:
Test the '/system/pipelines/' endpoint with a simple XSS payload like '<script>alert(1)</script>' in URL parameters and check if it executes in the response.Check Version:
grep -i version /etc/graylog/server/server.conf or check the web interface footer.Verify Fix Applied:
After patching, repeat the XSS test; the payload should be properly encoded and not execute.📡 Detection & Monitoring
Log Indicators:
- Unusual GET requests to '/system/pipelines/' with script tags or JavaScript code in URL parameters.
- Multiple failed login attempts following suspicious URL accesses.
Network Indicators:
- HTTP requests containing malicious script payloads in query strings.
- Traffic spikes to Graylog web interface from unexpected sources.
SIEM Query:
source="graylog_access.log" AND uri_path="/system/pipelines/" AND (query_string="*<script>*" OR query_string="*javascript:*")