Vulnerability identifier: #VU66593

Vulnerability risk: Low

CVSSv3.1: 5.9 [CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-34557

CWE-ID: CWE-119

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
xscreensaver
Other software / Other software solutions

Vendor:

Description

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.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

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External links
http://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch
http://github.com/QubesOS/qubes-issues/issues/6595
http://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt
http://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
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/

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Q & A

Can this vulnerability be exploited remotely?

No. The attacker should have physical access to the system in order to successfully exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.