# RHSA-2021:5241: Security update for 12 packages

RHSA-2021:5241, released December 21, 2021, fixes 1 CVE across 12 products. None of them is reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/fix/linux/rhsa-2021-5241
- Platform: Linux
- Released: Dec 21, 2021
- Priority: Routine (Closes CVE-2021-20321)
- CVEs: 1, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://access.redhat.com/errata/RHSA-2021:5241

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [kernel-rt](https://patchblox.com/security/data/product/linux/kernel-rt.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-core](https://patchblox.com/security/data/product/linux/kernel-rt-core.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-debug](https://patchblox.com/security/data/product/linux/kernel-rt-debug.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-debug-core](https://patchblox.com/security/data/product/linux/kernel-rt-debug-core.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-debug-devel](https://patchblox.com/security/data/product/linux/kernel-rt-debug-devel.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-debug-kvm](https://patchblox.com/security/data/product/linux/kernel-rt-debug-kvm.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-debug-modules](https://patchblox.com/security/data/product/linux/kernel-rt-debug-modules.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-debug-modules-extra](https://patchblox.com/security/data/product/linux/kernel-rt-debug-modules-extra.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-devel](https://patchblox.com/security/data/product/linux/kernel-rt-devel.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-kvm](https://patchblox.com/security/data/product/linux/kernel-rt-kvm.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-modules](https://patchblox.com/security/data/product/linux/kernel-rt-modules.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |
| [kernel-rt-modules-extra](https://patchblox.com/security/data/product/linux/kernel-rt-modules-extra.md) | RHEL 8 | 0:4.18.0-348.7.1.rt7.137.el8_5 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-20321](https://patchblox.com/security/data/cve/CVE-2021-20321.md) | Routine | bpftool: The kernel packages contain the Linux kernel, the core of any Linux operating system.  Security Fix(es):  * kernel: I... | 5.5 | 0.0022 |  |

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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