CVE-2020-26241 json
Shallow copy bug in geth
published 2020-11-25 5 y ago modified 2026-07-08 4 mo ago also GHSA-69v6-xc2j-r2jf , GO-2022-0771 , EUVD-2021-1275
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.2%
- EPSS 1.2% chance of exploitation in 30 days, percentile 69%
- public exploits
- 0
- none known
Summary
Go Ethereum, or "Geth", is the official Golang implementation of the Ethereum protocol. This is a Consensus vulnerability in Geth before version 1.9.17 which can be used to cause a chain-split where vulnerable nodes reject the canonical chain. Geth's pre-compiled dataCopy (at 0x00...04) contract did a shallow copy on invocation. An attacker could deploy a contract that writes X to an EVM memory region R, then calls 0x00..04 with R as an argument, then overwrites R to Y, and finally invokes the RETURNDATACOPY opcode. When this contract is invoked, a consensus-compliant node would push X on the EVM stack, whereas Geth would push Y. This is fixed in version 1.9.17.
Patch / fix
- go github.com/ethereum/go-ethereum 1.9.17
- ethereum go_ethereum 1.9.17
- govulncheck-vulndb openSUSE Tumbleweed 0.0.20250807T150727-1.1
opensuse advisories openSUSE-SU-2025:15424-1
Exploit prediction
1.23% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| NVD | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L |
| NVD | 2.0 | 5.5 | AV:N/AC:L/Au:S/C:N/I:P/A:P |
| GitHub | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/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 | >=1.9.7, <1.9.17 |
1.9.17 |
Affected products
- ethereum go-ethereum
Classification
- Weakness
-
- CWE-682 Incorrect Calculation
References
-
github.com
/ethereum/go-ethereum/commit/295693759e5ded05fec0b2fb39359965b60da785
web, patch
-
blog.ethereum.org
/2020/11/12/geth_security_release/
vendor-advisory
-
github.com
/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf
web, third-party-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2020-26241
advisory
-
blog.ethereum.org
/2020/11/12/geth_security_release
web
-
github.com
/ethereum/go-ethereum
package
Sources
- CVE List CVE-2020-26241
- GitHub Advisory GHSA-69v6-xc2j-r2jf
- NVD CVE-2020-26241
- OSV GO-2022-0771
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