CVE-2021-3939

HIGH

Ubuntu accountsservice <0.6.55-0ubuntu12~20.04.5 - Use After Free

Title source: llm

Description

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.

References (3)

[Broken Link] https://bugs.launchpad.net/ubuntu/+source/accountsservice/+bug/1950149

[Vendor Advisory] https://ubuntu.com/security/notices/USN-5149-1

[Exploit, Third Party Advisory] http://packetstormsecurity.com/files/172848/Ubuntu-accountsservice-Double-Free-Memory-Corruption.html

Scores

CVSS v3 7.8

EPSS 0.0012

EPSS Percentile 31.2%

Attack Vector LOCAL

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Details

CWE

CWE-590 CWE-763

Status published

Products (4)

canonical/accountsservice 0.6.55-0ubuntu12\~20.04 - 0.6.55-0ubuntu12\~20.05

canonical/ubuntu_linux 20.04

canonical/ubuntu_linux 21.04

canonical/ubuntu_linux 21.10

Published Nov 17, 2021

Tracked Since Feb 18, 2026