What is the CVSS score of CVE-2021-34557?

CVE-2021-34557 has a CVSS 3.1 base score of 4.6 (Medium). CVSS vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2021-34557?

Yes, a public proof-of-concept exploit is available for CVE-2021-34557. Prioritise patching immediately. EPSS: 0.5%.

Is there a patch available for CVE-2021-34557?

Yes, a patch is available for CVE-2021-34557. Update the affected software to the latest version immediately.

Xscreensaver CVE-2021-34557

MEDIUM

Classic Buffer Overflow (CWE-120)

2021-06-10 cve@mitre.org

Buffer Overflow Xscreensaver Fedora

4.6

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.6 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

None

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Jun 10, 2021 - 16:15 nvd

MEDIUM 4.6

DescriptionNVD

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.

AnalysisAI

XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. Rated medium severity (CVSS 4.6), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified as Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. 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. Affected products include: Xscreensaver Project Xscreensaver, Fedoraproject Fedora.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.