Buffer overflow in xscreensaver - CVE-2021-34557

Vulnerability identifier: #VU66593

CSH Severity: Low

CVSS v4: 7 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-34557

CWE-ID: CWE-119

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows an attacker to escalate privileges on the system.

The vulnerability exists due to a boundary error within the update_screen_layout()  function. An attacker with physical access to the system can trigger memory corruption and bypass the standard screen lock authentication mechanism.

xscreensaver
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE Linux Enterprise Storage
SUSE Linux Enterprise Server
SUSE Linux Enterprise Desktop
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Module for Basesystem
SUSE Linux Enterprise Server for SAP Applications
openSUSE Leap
Fedora
xscreensaver
xscreensaver-data
xscreensaver-data-debuginfo
xscreensaver-debuginfo
xscreensaver-debugsource
xscreensaver-data-extra
xscreensaver-data-extra-debuginfo
xscreensaver-lang

Install updates from vendor's website.

xscreensaver - update to 5.45-5
xscreensaver - addressed in versions 5.22-8.3.1, 5.44-150000.5.6.1
xscreensaver-data - addressed in versions 5.22-8.3.1, 5.44-150000.5.6.1
xscreensaver-data-debuginfo - addressed in versions 5.22-8.3.1, 5.44-150000.5.6.1
xscreensaver-debuginfo - addressed in versions 5.22-8.3.1, 5.44-150000.5.6.1
xscreensaver-debugsource - addressed in versions 5.22-8.3.1, 5.44-150000.5.6.1
xscreensaver-data-extra - update to 5.44-150000.5.6.1
xscreensaver-data-extra-debuginfo - update to 5.44-150000.5.6.1
xscreensaver-lang - update to 5.44-150000.5.6.1
xscreensaver - update to 5.45-2.fc33

• https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch
• https://github.com/QubesOS/qubes-issues/issues/6595
• https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt
• https://www.openwall.com/lists/oss-security/2021/06/05/1
• http://www.openwall.com/lists/oss-security/2021/06/11/1
• http://www.openwall.com/lists/oss-security/2021/07/06/2
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/

• Lock screen bypass in XScreenSaver
• SUSE update for xscreensaver
• SUSE update for xscreensaver
• Fedora 33 update for xscreensaver