# RHSA-2021:3547: Security update for 12 packages

RHSA-2021:3547, released September 15, 2021, fixes 1 CVE across 12 products. None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/linux/rhsa-2021-3547
- Platform: Linux
- Released: Sep 15, 2021
- Priority: High (Closes CVE-2021-3653, high severity)
- CVEs: 1, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://access.redhat.com/errata/RHSA-2021:3547

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [kernel-rt](https://patchblox.com/security/data/product/linux/kernel-rt.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-core](https://patchblox.com/security/data/product/linux/kernel-rt-core.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-debug](https://patchblox.com/security/data/product/linux/kernel-rt-debug.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-debug-core](https://patchblox.com/security/data/product/linux/kernel-rt-debug-core.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-debug-devel](https://patchblox.com/security/data/product/linux/kernel-rt-debug-devel.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-debug-kvm](https://patchblox.com/security/data/product/linux/kernel-rt-debug-kvm.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-debug-modules](https://patchblox.com/security/data/product/linux/kernel-rt-debug-modules.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-debug-modules-extra](https://patchblox.com/security/data/product/linux/kernel-rt-debug-modules-extra.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-devel](https://patchblox.com/security/data/product/linux/kernel-rt-devel.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-kvm](https://patchblox.com/security/data/product/linux/kernel-rt-kvm.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-modules](https://patchblox.com/security/data/product/linux/kernel-rt-modules.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |
| [kernel-rt-modules-extra](https://patchblox.com/security/data/product/linux/kernel-rt-modules-extra.md) | RHEL 8 | 0:4.18.0-305.19.1.rt7.91.el8_4 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-3653](https://patchblox.com/security/data/cve/CVE-2021-3653.md) | High | kernel-rt-debug-modules: The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high... | 8.8 | 0.0045 |  |

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Data as of 2026-11-07T12:40:37Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo