UBUNTU-CVE-2026-39821

Affected: Ubuntu:14.04:LTS: golang-1.10, Ubuntu:16.04:LTS: golang-1.10, Ubuntu:16.04:LTS: golang-1.6, Ubuntu:Pro:16.04:LTS: juju-core, Ubuntu:Pro:16.04:LTS: lxd, Ubuntu:Pro:16.04:LTS: containerd, Ubuntu:Pro:16.04:LTS: golang-1.13, Ubuntu:Pro:16.04:LTS: golang-1.18, Ubuntu:Pro:16.04:LTS: google-guest-agent, Ubuntu:Pro:16.04:LTS: google-osconfig-agent and 55 more

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".

Most recent entries from all

UBUNTU-CVE-2026-39821