Import Source
https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-87726.json
JSON Data
https://api.osv.dev/v1/vulns/AZL-87726
Upstream
Published
2026-05-22T16:16:20Z
Modified
2026-08-28T17:48:04Z
Summary
CVE-2026-39821 affecting package etcd for versions less than 3.5.30-2
Details

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

Affected packages

Azure Linux:3 / etcd

Package

Name
etcd
Purl
pkg:rpm/azure-linux/etcd

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.5.30-2

Database specific

source
"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-87726.json"