CVE-2026-27614
📋 TL;DR
This is a stored cross-site scripting (XSS) vulnerability in Bugsink error tracking software. Unauthenticated attackers who can submit error events to a Bugsink project can inject malicious JavaScript that executes when administrators view those events in the web interface. This affects all Bugsink instances running vulnerable versions that accept external error submissions.
💻 Affected Systems
- Bugsink
📦 What is this software?
Bugsink by Bugsink
⚠️ Risk & Real-World Impact
Worst Case
Administrator account takeover leading to complete compromise of the Bugsink instance, data exfiltration, or lateral movement within the network if the administrator has elevated privileges.
Likely Case
Session hijacking of administrator accounts, unauthorized access to sensitive error data, or manipulation of Bugsink configuration and data.
If Mitigated
Limited impact if proper network segmentation prevents external attackers from reaching the Bugsink ingest endpoint or if administrators use browsers with strong XSS protections.
🎯 Exploit Status
Exploitation requires knowledge of a project's DSN (which may be embedded in client applications) and ability to reach the Bugsink ingest endpoint. The vulnerability is straightforward to exploit once these conditions are met.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.13
Vendor Advisory: https://github.com/bugsink/bugsink/security/advisories/GHSA-vp6q-7m36-pq3w
Restart Required: Yes
Instructions:
1. Backup your Bugsink instance and database. 2. Update to version 2.0.13 using your package manager or by downloading from GitHub releases. 3. Restart the Bugsink service. 4. Verify the update was successful by checking the version.
🔧 Temporary Workarounds
Restrict Ingest Endpoint Access
linuxBlock external access to Bugsink DSN endpoints while allowing internal clients to submit events.
# Configure firewall rules to restrict access to Bugsink port (default 9000) to internal IPs only
# Example iptables: iptables -A INPUT -p tcp --dport 9000 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 9000 -j DROP
Content Security Policy
allImplement strict Content Security Policy headers to mitigate XSS impact.
# Add to web server configuration (nginx example):
add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval';" always;
🧯 If You Can't Patch
- Implement network segmentation to restrict access to Bugsink ingest endpoints to trusted internal networks only.
- Monitor administrator activity logs for suspicious event viewing patterns and implement alerting for unusual JavaScript content in error events.
🔍 How to Verify
Check if Vulnerable:
Check Bugsink version: if running any version below 2.0.13, the system is vulnerable.Check Version:
Check Bugsink web interface admin panel or run: bugsink --versionVerify Fix Applied:
Confirm version is 2.0.13 or higher and test that JavaScript in error stack traces is properly sanitized when viewed.📡 Detection & Monitoring
Log Indicators:
- Unusual error submissions with JavaScript content
- Administrator viewing events with suspicious payloads
- Multiple failed authentication attempts following administrator event views
Network Indicators:
- External IP addresses accessing DSN endpoints
- Unusual patterns of error submissions
SIEM Query:
source="bugsink" AND (event="error_submission" AND message="*<script>*" OR event="admin_view" AND user_agent="*Mozilla*" AND referrer="*/events/*")