CVE-2025-23020
📋 TL;DR
A hash collision vulnerability in Kwik's connection management hash table allows remote attackers to cause high CPU load through Hash DoS attacks by initiating connections with colliding Source Connection IDs. This affects all Kwik servers running vulnerable versions, potentially degrading service availability. The vulnerability is network-accessible and requires no authentication.
💻 Affected Systems
- Kwik
⚠️ 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 degradation or denial of service due to sustained high CPU consumption, making the server unresponsive to legitimate traffic.
Likely Case
Significant performance degradation and increased latency for legitimate connections, potentially causing partial service disruption.
If Mitigated
Minimal impact with proper rate limiting, connection limits, and monitoring in place to detect and block attack patterns.
🎯 Exploit Status
The advisory includes technical details and the attack leverages known hash collision techniques against QUIC implementations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.10.1
Vendor Advisory: https://github.com/ptrd/kwik/releases/tag/v0.10.1
Restart Required: Yes
Instructions:
1. Stop the Kwik service. 2. Update to version 0.10.1 or later. 3. Restart the Kwik service.
🔧 Temporary Workarounds
Rate limiting connections
allImplement connection rate limiting to reduce the impact of hash collision attacks
# Configure via your load balancer or firewall rules
# Example: iptables -A INPUT -p udp --dport <kwik_port> -m limit --limit 100/second -j ACCEPT
Connection limits
linuxLimit maximum concurrent connections to reduce attack surface
# Configure in Kwik settings if available
# Use system limits: ulimit -n <max_open_files>
🧯 If You Can't Patch
- Implement network-level rate limiting and connection throttling
- Deploy behind a WAF or load balancer with DoS protection capabilities
🔍 How to Verify
Check if Vulnerable:
Check Kwik version: if version is less than 0.10.1, the system is vulnerable.Check Version:
kwik --version or check the running process/package versionVerify Fix Applied:
Confirm Kwik version is 0.10.1 or later and monitor CPU usage during normal operation.📡 Detection & Monitoring
Log Indicators:
- Unusually high number of new connection attempts
- Sustained high CPU usage alerts
- Connection timeouts or failures
Network Indicators:
- High volume of QUIC connection initiation packets
- Pattern of connections with similar SCID values
- Unusual traffic spikes on Kwik service port
SIEM Query:
source="kwik" AND (cpu_usage>90 OR connection_count>threshold)