GitHub Advisoryadvisory · Go

GHSA-xg2h-wx96-xgxr RandomAlphaNumeric and CryptoRandomAlphaNumeric are not as random as they should be

LOW Published 2021-05-21 Modified 2026-01-23 Official page ↗
Aliases
CVE-2021-4238
Ecosystem
Go
Packages
github.com/Masterminds/goutils
Severity
Low
Weaknesses
CWE-331
Reviewed
2021-05-21

Affected packages

• Go github.com/Masterminds/goutils: < 1.1.1 → fixed in 1.1.1

Description

Impact A security-sensitive bug was discovered by Open Source Developer *Erik Sundell of Sundell Open Source Consulting AB*. The functions `RandomAlphaNumeric(int)` and `CryptoRandomAlphaNumeric(int)` are not as random as they should be. Small values of `int` in the functions above will return a smaller subset of results than they should. For example, `RandomAlphaNumeric(1)` will always return a digit in the 0-9 range, while `RandomAlphaNumeric(4)` will return around ~7 million of the ~13M possible permutations. This is considered a security release because programs that rely upon random generators for passwords are at an increased risk of brute force-style password guessing. There is also a higher probability of collision. The problem was the result of a mistaken regular expression that only accepted random strings if they contained a digit from `[0-9]`. That restriction has been removed. Patches This issue has been corrected in v1.1.1. Workarounds If you cannot upgrade to v1.1.1, you can work around the issue by calling `RandomAlphaNumericCustom(N, true, true)`|`CryptoRandomAlphaNumericCustom(N, true, true)` instead. (Where `N` is the desired length, and `true` is the literal boolean `true`.)

Related

Alias · CVE (1)

  • CVE-2021-4238 Randomly-generated alphanumeric strings contain significantly less entropy than expected. vulnerability

Weakness · CWE (1)

  • CWE-331 Insufficient Entropy weakness

References