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CVE-2021-3543

23
FAUCET Score

CVE-2021-3543 describes a null pointer dereference vulnerability in the Nitro Enclaves kernel driver, impacting Fedora and Red Hat Enterprise Linux systems utilizing Nitro Enclaves. This flaw allows a local, highly privileged user on the host machine to crash the system or escalate their privileges. With a CVSS score of 6.7 (Medium), it requires local access and high privileges but has a high impact on confidentiality, integrity, and availability. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.10.0CPE matchmatch criteria
cpe:2.3:a:nitro_enclaves_project:nitro_enclaves:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.7MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
0.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.30%
Probability of exploitation in next 30 days
EPSS Percentile
22.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0030 is in the 69th percentile among its peer group of 3,720 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-305.3.1.rt7.75.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-305.3.1.el8_4
View patch

Vendor Advisories (1)

redhatCVE-2021-3543Moderate

kernel: nitro_enclaves stale file descriptors on failed usercopy

Apr 29, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party Advisory
lore.kernel.org / lkml/20210429165941.27020-2-andraprs%40amazon.com