How severe is CVE-2021-34557?

CVE-2021-34557 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-34557 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34557?

CVE-2021-34557 primarily affects Xscreensaver Project Xscreensaver. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-34557?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-34557 published?

CVE-2021-34557 was published on 2021-06-10 and last updated on 2026-06-17.

CVE-2021-34557

CVE-2021-34557 is a medium-severity vulnerability in Xscreensaver Project Xscreensaver with a CVSS 3.x base score of 4.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: Medium (CVSS 3.x base score 4.6)
CVSS v2: 2.1
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Xscreensaver Project Xscreensaver
Published: 2021-06-10
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-34557?: CVE-2021-34557 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-34557 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34557?: CVE-2021-34557 primarily affects Xscreensaver Project Xscreensaver. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-34557?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-34557 published?: CVE-2021-34557 was published on 2021-06-10 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:xscreensaver_project:xscreensaver:5.45:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

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