Kurz gesagt
- CVE-2020-26241 ist eine Schwachstelle (HOCH (CVSS 7.1)) in github.com/ethereum/go-ethereum, go ethereum (ethereum).
- Wahrscheinlichkeit einer Ausnutzung in den nächsten 30 Tagen (EPSS): 1.2%, höher als bei 68.8% aller Schwachstellen.
- Abhilfe: auf 1.9.17 oder neuer aktualisieren.
Description
Impact
This is a Consensus vulnerability, 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,
- calls
0x00..04 with R as an argument,
- 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.
Patches
No standalone patches have been made.
Workarounds
Upgrade to 1.9.17 or higher.
References
https://blog.ethereum.org/2020/11/12/geth_security_release/
For more information
If you have any questions or comments about this advisory:
NVD 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.
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