CVE-2021-20315

A locking protection bypass flaw was found in some versions of gnome-shell as shipped within CentOS Stream 8, when the "Application menu" or "Window list" GNOME extensions are enabled. This flaw allows a physical attacker who has access to a locked system to kill existing applications and start new ones as the locked user, even if the session is still locked.

Published: 2022-02-18 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20315 is rated Low Risk (27.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.04%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-20315

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 0.05% 0.04% -0.01%
2 2025-03-29 0.04% 0.05% +0.01%
3 2025-03-17 — 0.04% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20315

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:P)
Hands-on access—USB, keyboard, opening the case—not something you do purely over the wire.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 0.9 5.2 [email protected]
3.6 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 4.9 [email protected]

Weakness enumeration for CVE-2021-20315

OS Trackers for CVE-2021-20315

vendor priority summary link
debian unimportant CVE-2021-20315 unimportant priority: Debian including 1 source packages (gnome-shell), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-20315
redhat medium — https://access.redhat.com/security/cve/CVE-2021-20315
suse medium CVE-2021-20315 severity moderate: SUSE including 5 source package names (gnome-shell, gnome-shell-browser-plugin, gnome-shell-calendar, gnome-shell-devel, gnome-shell-lang), 76 product×package rows across 30 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (30 product lines)): Known Not Affected 76. https://www.suse.com/security/cve/CVE-2021-20315/
ubuntu medium CVE-2021-20315 medium priority: Ubuntu including 1 source packages (gnome-shell), 6 status rows across 6 suites (bionic, focal, hirsute, trusty, upstream, xenial): not-affected 4, DNE 1, needs-triage 1. https://ubuntu.com/security/CVE-2021-20315

Affected software / configurations for CVE-2021-20315

Vendor Product Version Raw CPE
gnome gnome-shell < 3.32.2 cpe:2.3:a:gnome:gnome-shell:*:*:*:*:*:*:*:*
centos stream 8 cpe:2.3:o:centos:stream:8:*:*:*:*:*:*:*

References for CVE-2021-20315

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=2006285 Issue Tracking Third Party Advisory
cvelogic Threat Intelligence