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This vulnerability exploits the peer-to-peer (p2p) network stack of a go-ethereum (Geth) client. An attacker can construct and send a specially crafted network message to a targeted node. The malicious message is designed to trigger an inefficient processing path or cause the node’s state handling logic to enter a computationally expensive loop. When the node receives and begins to process this message, it will consume nearly 100% of a CPU core’s resources for an extended duration. This stalls the processing of legitimate transactions and blocks, and prevents meaningful communication with other peers. If an attacker sustains this attack by sending multiple such messages or targeting multiple CPU cores, they can render the node unresponsive, effectively causing a localized Denial of Service (DoS). The node may fall out of sync with the network and require a restart to recover normal function.
Platform: Go-Ethereum (Geth)
Version: Multiple versions
Vulnerability: P2P Message DoS
Severity: High
Date: 2026-01-13
Prediction: Patch by 2026-01-27
What Undercode Say:
Monitor for high CPU usage in Geth process top -p $(pgrep geth) Check peer connection counts for anomalies geth attach --exec "net.peerCount" Analyze p2p message logs for spikes tail -f /var/log/geth/chaindata/p2p.log | grep -E "(error|unexpected)"
How Exploit:
Attacker crafts malformed p2p packet and sends to victim’s node on discovery or eth protocol port (typically UDP/30303, TCP/30303). The payload contains data that causes the message handler to perform excessive computations, such as a deeply nested structure requiring non-linear processing time.
Protection from this CVE:
Apply official Geth security patch immediately upon release. Temporarily restrict p2p inbound connections using firewall rules to trusted peers only. Monitor node CPU metrics and implement automated alerts for sustained high usage.
Impact:
Node unavailability, network synchronization failure, reduced network health, potential eclipse attack vector if combined with other flaws.
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Sources:
Reported By: github.com
Extra Source Hub:
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