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Fencer Intel
medium 5.3

CVE-2020-26265 json

Consensus flaw during block processing

published 5y ago modified last mo. also GHSA-xw37-57qp-9mm4 , GO-2021-0105 , EUVD-2021-1427

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 60%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/ethereum/go-ethereum 1.9.20
  • ethereum go_ethereum 1.9.20
  • go-ethereum Arch Linux 1.9.20-1

arch linux advisories AVG-1353

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Exploit prediction

0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/ethereum/go-ethereum
>=1.9.4, <1.9.20
1.9.20

Affected products

  • ethereum go-ethereum

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.