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CVE-2021-34557

18
FAUCET Score

CVE-2021-34557 is a buffer overflow vulnerability in XScreenSaver 5.45 that allows an attacker to bypass the screen lock authentication mechanism. This vulnerability affects Fedora and XScreenSaver products. It has a CVSS score of 4.6 (Medium) and requires physical access to the machine to disconnect more than ten video outputs, leading to a denial of service that bypasses the lock. There is no known active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
5.45CPE matchmatch criteria
cpe:2.3:a:xscreensaver_project:xscreensaver:5.45:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.6MEDIUM

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

Attack Vector
PHYSICAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
0.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.48%
Probability of exploitation in next 30 days
EPSS Percentile
38.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0048 is in the 76th percentile among its peer group of 1,531 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.2 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / QubesOS/qubes-issues/issues/6595
Issue TrackingThird Party Advisory
github.com / QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt
ExploitThird Party Advisory
github.com / QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch
PatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/TC4QB7TRS4GS7LDXQQ4PC6J3LVFJYISV
openwall.com / lists/oss-security/2021/06/05/1
ExploitMailing ListThird Party Advisory
openwall.com / lists/oss-security/2021/06/11/1
Mailing ListThird Party Advisory
openwall.com / lists/oss-security/2021/07/06/2
ExploitMailing ListThird Party Advisory