Improper Validation of Unsafe Equivalence in Input Affecting go-toolset package, versions *


Severity

Recommended
0.0
high
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.36% (28th percentile)

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  • Snyk IDSNYK-CENTOS8-GOTOOLSET-17283739
  • published10 Jun 2026
  • disclosed22 May 2026

Introduced: 22 May 2026

NewCVE-2026-39821  (opens in a new tab)
CWE-1289  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 go-toolset.

NVD Description

Note: Versions mentioned in the description apply only to the upstream go-toolset package and not the go-toolset package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject "example.com" but permit "xn--example-.com". If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name "example.com".

CVSS Base Scores

version 3.1