CVE-2026-26313: Go-Ethereum (Geth) DoS Vulnerability

CVE-2026-26313 Overview

CVE-2026-26313 is a resource exhaustion vulnerability in go-ethereum (geth), the golang execution layer implementation of the Ethereum protocol. Prior to version 1.17.0, an attacker can cause high memory usage by sending a specially-crafted peer-to-peer (p2p) message to a vulnerable geth node. This vulnerability allows remote attackers to potentially degrade the performance or availability of Ethereum nodes running affected versions of geth.

Critical Impact

Remote attackers can exploit this vulnerability to exhaust memory resources on Ethereum nodes by sending malicious p2p messages, potentially causing denial of service conditions that could disrupt blockchain network operations.

Affected Products

• go-ethereum (geth) versions prior to 1.17.0
• Ethereum nodes running vulnerable geth implementations
• Infrastructure relying on affected geth versions for blockchain operations

Discovery Timeline

• 2026-02-19 - CVE-2026-26313 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-26313

Vulnerability Analysis

This vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling). The flaw exists in how geth processes incoming peer-to-peer messages within the Ethereum network protocol. When a specially-crafted p2p message is received, the node fails to properly limit memory allocation during message processing, allowing an attacker to trigger excessive memory consumption.

The network-accessible nature of this vulnerability makes it particularly concerning for public-facing Ethereum nodes. An attacker does not require any privileges or user interaction to exploit this flaw—they simply need network connectivity to the target node's p2p communication port.

Root Cause

The root cause of CVE-2026-26313 lies in improper resource allocation controls within the p2p message handling code. The vulnerable code path does not enforce adequate limits on memory allocation when processing certain message types, allowing malicious actors to craft messages that consume disproportionate amounts of memory relative to their size.

Attack Vector

The attack is conducted over the network through the Ethereum p2p protocol. An attacker can connect to a vulnerable geth node and send specially-crafted messages designed to trigger the memory exhaustion condition. Since geth nodes typically need to accept connections from peers on the Ethereum network, this attack surface is inherently exposed.

The vulnerability can be exploited without authentication or any special privileges. Repeated exploitation could lead to memory exhaustion, causing the node to become unresponsive or crash, effectively resulting in a denial of service condition.

Detection Methods for CVE-2026-26313

Indicators of Compromise

• Unusual memory consumption spikes on geth nodes without corresponding increases in legitimate network activity
• Unexpected connections from suspicious IP addresses to the p2p communication port
• Geth process crashes or restarts with out-of-memory errors in system logs
• Degraded node performance or sync issues correlating with specific peer connections

Detection Strategies

• Monitor geth process memory utilization and alert on abnormal growth patterns
• Implement network traffic analysis to identify anomalous p2p message patterns or sizes
• Review geth logs for connection attempts from unknown or suspicious peers
• Deploy intrusion detection signatures targeting malformed Ethereum p2p protocol messages

Monitoring Recommendations

• Configure memory usage alerts for geth processes with appropriate thresholds based on baseline behavior
• Implement peer reputation tracking to identify potentially malicious connection sources
• Enable detailed logging for p2p network events to facilitate forensic analysis
• Consider deploying network-level monitoring to detect volumetric anomalies in p2p traffic

How to Mitigate CVE-2026-26313

Immediate Actions Required

• Upgrade go-ethereum (geth) to version 1.17.0 or later immediately
• Review network access controls to limit p2p port exposure where possible
• Monitor affected nodes for signs of exploitation while patching is in progress
• Consider temporarily reducing peer connection limits as a defensive measure

Patch Information

The vulnerability has been resolved in go-ethereum version 1.17.0. Organizations running affected versions should upgrade immediately. The fix is available through the official GitHub Release v1.17.0. Additional details about the vulnerability and remediation can be found in the GitHub Security Advisory GHSA-689v-6xwf-5jf3.

Workarounds

• Implement network-level filtering to restrict p2p port access to trusted peers only
• Configure firewall rules to rate-limit incoming connections on the p2p port
• Deploy geth behind a reverse proxy or load balancer with connection limiting capabilities
• Monitor and automatically restart geth processes that exhibit memory exhaustion symptoms

# Example: Upgrade geth to patched version
# Stop the current geth service
sudo systemctl stop geth

# Download and install geth v1.17.0 or later
# Follow official installation instructions for your platform
# https://github.com/ethereum/go-ethereum/releases/tag/v1.17.0

# Restart the geth service
sudo systemctl start geth

# Verify the version
geth version