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The vulnerability exists in the Go Ethereum (Geth) client’s peer-to-peer (p2p) connection handshake mechanism. During the handshake process, both parties compute a shared secret key using Elliptic Curve (EC) cryptography. The vulnerable implementations failed to validate whether the EC public key provided by the remote peer is actually a valid point on the secp256k1 curve . By sending a specially crafted message containing an all-zero public key, an attacker can trigger unexpected results during the handshake computation . This lack of input validation leads to a critical error in the cryptographic routine, causing the node to crash or shut down abruptly . The crash results from unhandled edge cases when the invalid curve point is processed, forcing the entire Geth client to terminate . This creates a Denial of Service (DoS) condition, effectively removing the targeted node from the Ethereum network . The issue was resolved by adding a proper curve point validity check before processing the public key .
DailyCVE Form
Platform: go-ethereum
Version: Prior to 1.14.13
Vulnerability: Denial of Service
Severity: Moderate
Date: Feb 18, 2026
Prediction: Already Patched
What Undercode Say:
`$ geth version`
Check current Geth version geth version | grep "Version:" Expected output for vulnerable versions Version: 1.14.12-stable or earlier Patched version check Version: 1.14.13-stable or later
`$ netstat -tulpn | grep geth`
Monitor active Geth connections netstat -tulpn | grep geth Watch for suspicious peer connections watch -n 2 'netstat -tulpn | grep geth | wc -l' Log all incoming connections sudo tcpdump -i any port 30303 -c 100 -w geth_traffic.pcap
`$ tail -f /var/log/geth.log`
Monitor Geth logs for crash events
tail -f /var/log/geth.log | grep -E "panic|fatal|crash|segmentation"
Check for handshake errors before crash
grep -i "handshake" /var/log/geth.log | tail -20
Monitor memory usage spikes
while true; do
ps aux | grep geth | grep -v grep | awk '{print $2, $4, $6}'
sleep 5
done
`$ go get github.com/ethereum/[email protected]`
Update to patched version go get -u github.com/ethereum/[email protected] Verify update go list -m github.com/ethereum/go-ethereum Clean and rebuild go clean -modcache go mod tidy go build ./cmd/geth
How Exploit:
- Identify vulnerable Geth node running version prior to 1.14.13
- Craft malicious P2P handshake message with all-zero secp256k1 public key
- Establish peer connection to target node on port 30303
4. Send specially crafted message during handshake phase
- Trigger invalid curve point computation causing node crash
- Target node terminates with fatal error or segmentation fault
Protection from this CVE
Update to Geth version 1.14.13 or later immediately . No workarounds are available as the vulnerability exists in core handshake logic . Implement network-level monitoring for unusual handshake patterns. Deploy fail2ban rules to temporarily block peers exhibiting suspicious behavior. Maintain multiple node instances for redundancy during attack scenarios .
Impact
Complete node shutdown and removal from Ethereum network . Loss of network participation and inability to process blocks or transactions . Potential disruption to dependent services and applications relying on the affected node. Chain synchronization may be interrupted, requiring manual restart . Multiple nodes could be targeted simultaneously, affecting network stability .
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Sources:
Reported By: github.com
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