CVE-2021-3939: Canonical Accountsservice

High severity, CVSS 7.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Ubuntu-specific modifications to accountsservice (in patch file debian/patches/0010-set-language.patch) caused the fallback_locale variable, pointing to static storage, to be freed, in the user_change_language_authorized_cb function. This is reachable via the SetLanguage dbus function. This is fixed in versions 0.6.55-0ubuntu12~20.04.5, 0.6.55-0ubuntu13.3, 0.6.55-0ubuntu14.1.

Affected products

• Canonical Accountsservice: from 0.6.55-0ubuntu12\~20.04, before 0.6.55-0ubuntu12\~20.05 (fixed in 0.6.55-0ubuntu12\~20.05); from 0.6.55-0ubuntu13, before 0.6.55-0ubuntu13.3 (fixed in 0.6.55-0ubuntu13.3); from 0.6.55-0ubuntu14, before 0.6.55-0ubuntu14.1 (fixed in 0.6.55-0ubuntu14.1)
• Canonical Ubuntu Linux: version 20.04 only; version 21.04 only; version 21.10 only

Published 2021-11-17. Last modified 2026-06-17.