CVE-2018-17071

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2018-09-18 · updated 2026-06-17
Weakness: CWE-338

Description

The fallback function of a simple lottery smart contract implementation for Lucky9io, an Ethereum gambling game, generates a random value with the publicly readable variable entry_number. This variable is private, yet it is readable by eth.getStorageAt function. Also, attackers can purchase a ticket at a low price by directly calling the fallback function with small msg.value, because the developer set the currency unit incorrectly. Therefore, it allows attackers to always win and get rewards.

Affected products

Lucky9Io: all versions

References

https://github.com/TEAM-C4B/CVE-LIST/tree/master/CVE-2018-17071
https://github.com/TEAM-C4B/CVE-LIST/tree/master/CVE-2018-17071

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