Use after free in kernel
Priority LOW 29CWE-416Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution, Denial of service
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416, CWE-476 and the CVSS impact.
Summary
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.
Why it matters now
EPSS 0.00301 23rd percentileScored 2026-11-07
Fix Fixed Red Hat: 2 advisories
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | kernel | kernel 4.18.0 | — | No fix listed | CNA |
- kernel Vendor— Affected kernel 4.18.0 Fixed in — No fix listed CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:nitro_enclaves_project:nitro_enclaves:*:*:*:*:*:*:*:* | before 5.10.0 | Vulnerable | Nitro Enclaves Project |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 34 | Vulnerable | Fedoraproject |
- cpe:2.3:a:nitro_enclaves_project:nitro_enclaves:*:*:*:*:*:*:*:* Versions before 5.10.0 Vulnerable ·Nitro Enclaves Project
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
Remediation
Red Hat 2 advisories
- RHSA-2021:2168 Released 2021-06-01 · Red Hat rating Importantkernel security and bug fix update
- Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-305.3.1.el8_4
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-305.3.1.el8_4, kernel-4.18.0-305.3.1.el8_4, kernel-abi-stablelists-4.18.0-305.3.1.el8_4 +19
- RHSA-2021:2169 Released 2021-06-01 · Red Hat rating Importantkernel-rt security and bug fix update
- Red Hat Enterprise Linux Real Time (v. 8) kernel-rt-4.18.0-305.3.1.rt7.75.el8_4, kernel-rt-core-4.18.0-305.3.1.rt7.75.el8_4, kernel-rt-debug-4.18.0-305.3.1.rt7.75.el8_4 +7
- Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt-4.18.0-305.3.1.rt7.75.el8_4, kernel-rt-core-4.18.0-305.3.1.rt7.75.el8_4, kernel-rt-debug-4.18.0-305.3.1.rt7.75.el8_4 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat CodeReady Linux Builder (v. 8) | Fixed | RHSA-2021:2168 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2021:2168 |
| Red Hat Enterprise Linux Real Time (v. 8) | Fixed | RHSA-2021:2169 |
| Red Hat Enterprise Linux Real Time for NFV (v. 8) | Fixed | RHSA-2021:2169 |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-3543
- 2026-10-03 Alias added: GHSA-5rp3-9frh-m3wx
References
Sources
- CVE-2021-3543 · CVE Program
- CVE-2021-3543 · NVD
- FIRST EPSS
- GHSA-5rp3-9frh-m3wx · GitHub Advisory Database · CC BY 4.0
- CVE-2021-3543 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences