Race condition vulnerability in SDDM allows unauthorized access to X server

CVE-2020-28049 · MEDIUM Severity

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

An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.

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