What’s Vulnerable › Vulnerabilities

CVE-2020-26265: Consensus flaw during block processing

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-12-11 · updated 2026-06-17
• Weakness: CWE-682

Description

Go Ethereum, or "Geth", is the official Golang implementation of the Ethereum protocol. In Geth from version 1.9.4 and before version 1.9.20 a consensus-vulnerability could cause a chain split, where vulnerable versions refuse to accept the canonical chain. The fix was included in the Paragade release version 1.9.20. No individual workaround patches have been made -- all users are recommended to upgrade to a newer version.

Affected products

• ethereum go-ethereum: from 1.9.4 before 1.9.20 — fixed in 1.9.20

How to fix

Upgrade to a fixed version: ethereum go-ethereum 1.9.20. Check the vendor advisory for mitigations.

References

• https://github.com/ethereum/go-ethereum/releases/tag/v1.9.20
• https://github.com/ethereum/go-ethereum/security/advisories/GHSA-xw37-57qp-9mm4
• https://github.com/ethereum/go-ethereum/releases/tag/v1.9.20
• https://github.com/ethereum/go-ethereum/security/advisories/GHSA-xw37-57qp-9mm4

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