CVE-2021-34557 Memory corruption in n/a
A buffer overflow in XScreenSaver allows attackers to bypass screen lock authentication by physically disconnecting multiple video outputs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-34557?
CVE-2021-34557 is a medium-severity memory corruption vulnerability in Fedoraproject Fedora, published on 10 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-120
Which versions are affected by CVE-2021-34557?
It affects 2 products.
Linux distribution packages (4)
xscreensaver SUSE:Linux Enterprise Module for Basesystem 15 SP3 | All versions | 5.44-150000.5.6.1 |
xscreensaver SUSE:Linux Enterprise Server 12 SP5 | All versions | 5.22-8.3.1 |
xscreensaver SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 5.22-8.3.1 |
xscreensaver openSUSE:Leap 15.3 | All versions | 5.44-150000.5.6.1 |
Products include Fedoraproject Fedora, Xscreensaver Project Xscreensaver.
How do I fix CVE-2021-34557?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-34557 being exploited?
There is no known exploitation of CVE-2021-34557 in the wild and no public exploit code.
Other vulnerabilities in Fedoraproject Fedora
Sources
Also known as DEBIAN-CVE-2021-34557, GHSA-hrwv-325w-f6ch, MGASA-2021-0278, SUSE-SU-2022:2641-1, SUSE-SU-2022:2642-1, UBUNTU-CVE-2021-34557.