CVE-2021-34557: XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs.

Security readout for executives and security teams

This flaw affects XScreenSaver 5.45 screen locking. In a narrow physical-access scenario involving many disconnectable video outputs, XScreenSaver can crash and the locked session may become accessible without normal authentication. It is not a remote compromise, but it matters for workstations where physical access to a locked session is a meaningful risk. Exposure is likely limited to systems using XScreenSaver 5.45 as the active screen locker, especially Linux desktop environments with many external displays, docks, or video outputs. Business exposure depends on whether attackers can get physical access to locked machines. Treat this as a targeted physical-access workstation risk, not a broad network emergency. Prioritize sensitive desktops, shared labs, and administrator workstations where lock-screen bypass could expose confidential data or privileged sessions. Patch through normal endpoint maintenance unless high-risk physical access conditions exist. Mitigation focus: Update XScreenSaver using the applicable vendor or distribution advisory.; Apply QubesOS or Fedora package guidance where those platforms are in scope.; Reduce unattended physical access to workstations using XScreenSaver 5.45..

Prepared

Jun 2, 2026, 19:36 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.