Vulnerability Monitor

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CVE-2021-34557

XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. A buffer overflow in update_screen_layout() allows an attacker to bypass the standard screen lock authentication mechanism by crashing XScreenSaver. The attacker must physically disconnect many video outputs.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 4.6, with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 2 products from xscreensaver_project, from fedoraproject organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-06-10T16:15:08.227

Last Modified

2024-11-21T06:10:40.827

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 4.6 (MEDIUM)

CVSSv2 Vector

AV:L/AC:L/Au:N/C:N/I:N/A:P

Access Vector: LOCAL
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: PARTIAL

Exploitability Score

3.9

Impact Score

2.9

Weaknesses

Type: Primary
CWE-120

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	xscreensaver_project	xscreensaver	5.45	Yes
Operating System	fedoraproject	fedora	33	Yes

References

http://www.openwall.com/lists/oss-security/2021/06/11/1 Mailing List, Third Party Advisory ([email protected])
http://www.openwall.com/lists/oss-security/2021/07/06/2 Exploit, Mailing List, Third Party Advisory ([email protected])
https://github.com/QubesOS/qubes-issues/issues/6595 Issue Tracking, Third Party Advisory ([email protected])
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt Exploit, Third Party Advisory ([email protected])
https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch Patch, Third Party Advisory ([email protected])
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/ ([email protected])
https://www.openwall.com/lists/oss-security/2021/06/05/1 Exploit, Mailing List, Third Party Advisory ([email protected])
http://www.openwall.com/lists/oss-security/2021/06/11/1 Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.openwall.com/lists/oss-security/2021/07/06/2 Exploit, Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/QubesOS/qubes-issues/issues/6595 Issue Tracking, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV/ (af854a3a-2127-422b-91ae-364da2661108)
https://www.openwall.com/lists/oss-security/2021/06/05/1 Exploit, Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For xscreensaver_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.