CVE-2025-64509
📋 TL;DR
This vulnerability allows attackers to cause denial of service in Bugsink error tracking systems by sending specially crafted Brotli-compressed envelopes that consume excessive CPU during decompression. Attackers need knowledge of the DSN (Data Source Name), which is often exposed in common setups like JavaScript and mobile applications. All Bugsink instances running versions before 2.0.6 are affected.
💻 Affected Systems
- Bugsink
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to CPU exhaustion, preventing error tracking and potentially affecting dependent applications that rely on Bugsink for monitoring.
Likely Case
Degraded performance and intermittent service disruptions as CPU resources are consumed by malicious decompression requests.
If Mitigated
Minimal impact with proper rate limiting, network segmentation, and updated software.
🎯 Exploit Status
Exploitation requires crafting malicious Brotli-compressed payloads but doesn't require authentication if DSN is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.6
Vendor Advisory: https://github.com/bugsink/bugsink/security/advisories/GHSA-rrx3-2x4g-mq2h
Restart Required: Yes
Instructions:
1. Backup your Bugsink configuration and data. 2. Stop the Bugsink service. 3. Update to version 2.0.6 using your package manager or manual installation. 4. Restart the Bugsink service. 5. Verify the update was successful.
🔧 Temporary Workarounds
Rate Limiting
allImplement rate limiting on Bugsink endpoints to restrict the number of requests from single sources.
# Configure rate limiting in your web server or reverse proxy
# Example nginx: limit_req_zone $binary_remote_addr zone=bugsink:10m rate=10r/s;
Network Segmentation
linuxRestrict access to Bugsink endpoints to trusted networks only.
# Configure firewall rules to limit access
# Example iptables: iptables -A INPUT -p tcp --dport [BUGSINK_PORT] -s [TRUSTED_NETWORK] -j ACCEPT
🧯 If You Can't Patch
- Implement strict rate limiting and request validation to filter suspicious Brotli payloads.
- Isolate Bugsink instances in separate network segments with limited external access.
🔍 How to Verify
Check if Vulnerable:
Check your Bugsink version. If it's below 2.0.6, you are vulnerable.Check Version:
bugsink --version or check package manager (apt list --installed | grep bugsink)Verify Fix Applied:
Confirm Bugsink version is 2.0.6 or higher and monitor CPU usage during normal operation.📡 Detection & Monitoring
Log Indicators:
- Unusually high CPU usage by Bugsink process
- Multiple decompression errors or timeouts in logs
- Requests with abnormally large Brotli payloads
Network Indicators:
- High volume of requests to Bugsink endpoints from single sources
- Unusual patterns in Brotli-compressed traffic
SIEM Query:
source="bugsink" AND (cpu_usage>90 OR error="decompression" OR request_size>1000000)