CVE-2020-26241

Shallow copy bug in geth

Description

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.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.21%
Vendor Advisory ethereum.org
Affected: ethereum go-ethereum
Published at:
Updated at:

References

Link Tags
https://blog.ethereum.org/2020/11/12/geth_security_release/ vendor advisory
https://github.com/ethereum/go-ethereum/security/advisories/GHSA-69v6-xc2j-r2jf third party advisory

Frequently Asked Questions

What is the severity of CVE-2020-26241?
CVE-2020-26241 has been scored as a medium severity vulnerability.
How to fix CVE-2020-26241?
To fix CVE-2020-26241, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-26241 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2020-26241 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-26241?
CVE-2020-26241 affects ethereum go-ethereum.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.