How the CVE Works:
The vulnerability (CVE-2025-XXXX) in Netty QUIC (netty-incubator-codec-quic) arises from a hash collision flaw in the hash map managing QUIC connections. Attackers can exploit this by sending multiple QUIC handshake requests with specially crafted Source Connection IDs (SCIDs) that trigger hash collisions. This forces the server into excessive CPU usage due to inefficient hash bucket lookups, leading to a Denial-of-Service (DoS) condition. The attack does not require authentication and can degrade server performance significantly.
Netty QUIC versions below 0.0.71.Final are affected. The issue was patched in 0.0.71.Final by improving the hash distribution algorithm for SCID storage.
DailyCVE Form:
Platform: Netty QUIC
Version: < 0.0.71.Final
Vulnerability: Hash DoS
Severity: Moderate
Date: Mar 31, 2025
What Undercode Say:
Exploitation:
1. Craft malicious QUIC packets with colliding SCIDs.
2. Flood the server with handshake requests.
3. Monitor CPU spikes to confirm exploitation.
Detection:
Check Netty QUIC version mvn dependency:tree | grep "netty-incubator-codec-quic" Monitor CPU usage during QUIC handshakes top -c | grep "java"
Mitigation:
1. Upgrade to 0.0.71.Final or later.
2. Rate-limit QUIC handshakes to reduce attack impact.
3. Use load balancers to filter malicious traffic.
Proof-of-Concept (PoC) Snippet:
// Simulate colliding SCIDs
for (int i = 0; i < 10000; i++) {
QuicConnectionRequest request = new QuicConnectionRequest(generateCollidingSCID());
sendRequest(request);
}
Patch Analysis:
The fix modifies the hash function to prevent predictable collisions:
// Before (vulnerable) int hash = scid.hashCode(); // After (patched) int hash = secureHash(scid);
References:
References:
Reported By: https://github.com/advisories/GHSA-hqqc-jr88-p6x2
Extra Source Hub:
Undercode
