# Ethereum Contains Consensus Flaw During Block Processing

Advisory record · `GHSA-9856-9gg9-qcmq`

- **Identifiers:** `GHSA-9856-9gg9-qcmq` · `CVE-2021-39137` · `GO-2022-0254`
- **State:** Confirmed
- **Severity:** CVSS 6.5 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-436](https://cwe.mitre.org/data/definitions/436.html)
- **Tags:** [CWE-436](https://agentprime.io/advisories/tag/cwe-436.md)
- **Published:** 30 Aug 2021
- **Updated:** 8 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 30 Aug 2021, 16:15 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/ethereum/go-ethereum` (Go): affected `>=1.10.0, <1.10.8`; fixed in `1.10.8`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Geth (github.com/ethereum/go-ethereum) versions 1.10.0 up to but not including 1.10.8 are affected by a memory-corruption bug in the EVM that can cause nodes to compute different state roots when processing a maliciously crafted transaction, splitting the chain. An attacker can trigger this by submitting such a transaction, and it was exploited on Mainnet at block 13107518. Upgrade to version 1.10.8; no workarounds are listed.

Written 6 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 6.5 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.013, the 71st percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:05 UTC: First seen by agentprime
- 31 Oct 2026, 15:05 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-9856-9gg9-qcmq)

## Sources

- [GitHub Advisory Database: GHSA-9856-9gg9-qcmq](https://github.com/advisories/GHSA-9856-9gg9-qcmq)
- [OSV: GHSA-9856-9gg9-qcmq](https://osv.dev/vulnerability/GHSA-9856-9gg9-qcmq)
- <https://github.com/ethereum/go-ethereum/security/advisories/GHSA-9856-9gg9-qcmq>
- <https://nvd.nist.gov/vuln/detail/CVE-2021-39137>
- <https://github.com/ethereum/go-ethereum/pull/23381/commits/4d4879cafd1b3c906fc184a8c4a357137465128f>
- <https://github.com/ethereum/go-ethereum>
- <https://github.com/ethereum/go-ethereum/releases/tag/v1.10.8>
- <https://pkg.go.dev/vuln/GO-2022-0254>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-9856-9gg9-qcmq>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-9856-9gg9-qcmq/>. Everything for agents: <https://agentprime.io/llms.txt>.