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Fencer Intel
medium 5.9

CVE-2018-12885 json

The randMod() function of the smart contract implementation for MyCryptoChamp, an Ethereum game, generates a random value with publicly rea…

published 8y ago modified 4mo ago also EUVD-2018-4838

cvss
5.9
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

The randMod() function of the smart contract implementation for MyCryptoChamp, an Ethereum game, generates a random value with publicly readable variables such as the current block information and a private variable, (which can be read with a getStorageAt call). Therefore, attackers can get powerful champs/items and get rewards.

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Exploit prediction

1.39% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • medium.com https://medium.com/coinmonks/get-legendary-items-by-breaking-pnrg-of-mycyptochamp-an-ethereum-online-game-cve-2018-12855-6e6beb41b8df referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

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.