What’s Vulnerable › Vulnerabilities

CVE-2021-3543

• Severity: medium (CVSS 6.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-01 · updated 2026-06-17
• Weakness: CWE-416

Description

A flaw null pointer dereference in the Nitro Enclaves kernel driver was found in the way that Enclaves VMs forces closures on the enclave file descriptor. A local user of a host machine could use this flaw to crash the system or escalate their privileges on the system.

Affected products

• Fedoraproject Fedora: 34
• Nitro Enclaves Project Nitro Enclaves: before 5.10.0 — fixed in 5.10.0
• Red Hat Enterprise Linux: 8.0

How to fix

Upgrade to a fixed version: Nitro Enclaves Project Nitro Enclaves 5.10.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=1953022
• https://lore.kernel.org/lkml/20210429165941.27020-2-andraprs%40amazon.com/
• https://bugzilla.redhat.com/show_bug.cgi?id=1953022
• https://lore.kernel.org/lkml/20210429165941.27020-2-andraprs%40amazon.com/

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