CVE-2026-39821 Affecting golang-github-prometheus-prometheus package, versions <3.13.2-150100.4.40.2


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.69% (51st percentile)

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  • Snyk IDSNYK-SLES157-GOLANGGITHUBPROMETHEUSPROMETHEUS-20736006
  • published10 Oct 2026
  • disclosed9 Oct 2026

Introduced: 9 Oct 2026

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

How to fix?

Upgrade SLES:15.7 golang-github-prometheus-prometheus to version 3.13.2-150100.4.40.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream golang-github-prometheus-prometheus package and not the golang-github-prometheus-prometheus package as distributed by SLES. See How to fix? for SLES:15.7 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".

References

CVSS Base Scores

version 3.1