# CVE-2021-43784: runc: The runC tool is a lightweight, portable implementation of the Open Container Format (OCF) that provides container ru...

CVE-2021-43784 is fixed in runc on 1 platform, first by DEBIAN-CVE-2021-43784, released December 6, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-43784
- Priority: Routine
- CVSS: 5.0 (Moderate)
- EPSS: 0.0180
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 6, 2021

## Description

The runC tool is a lightweight, portable implementation of the Open Container Format (OCF) that provides container runtime.  Security Fix(es):  * golang: crypto/tls: large handshake records may cause panics (CVE-2022-41724)  * runc: Rootless runc makes `/sys/fs/cgroup` writable (CVE-2023-25809)  * runc: volume mount race condition (regression of CVE-2019-19921) (CVE-2023-27561)  * runc: AppArmor can be bypassed when `/proc` inside the container is symlinked with a specific mount configuration (CVE-2023-28642)  * runc: integer overflow in netlink bytemsg length field allows attacker to override netlink-based container configuration (CVE-2021-43784)  For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.  Additional Changes:  For detailed information on changes in this release, see the Red Hat Enterprise Linux 9.3 Release Notes linked from the References section.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | runc Debian 12.15 (bookworm) | 1.0.3+ds1-1 | [DEBIAN-CVE-2021-43784](https://patchblox.com/security/data/fix/linux/debian-cve-2021-43784.md) | Dec 6, 2021 |
| Linux | runc Debian 13.5 (trixie) | 1.0.3+ds1-1 | [DEBIAN-CVE-2021-43784](https://patchblox.com/security/data/fix/linux/debian-cve-2021-43784.md) | Dec 6, 2021 |
| Linux | runc Debian 14 | 1.0.3+ds1-1 | [DEBIAN-CVE-2021-43784](https://patchblox.com/security/data/fix/linux/debian-cve-2021-43784.md) | Dec 6, 2021 |
| Linux | runc RHEL 9 | 4:1.1.9-1.el9 | [RHSA-2023:6380](https://patchblox.com/security/data/fix/linux/rhsa-2023-6380.md) | Nov 7, 2023 |
| Linux | runc almalinux 9 | 4:1.1.9-1.el9 | [ALSA-2023:6380](https://patchblox.com/security/data/fix/linux/alsa-2023-6380.md) | Nov 7, 2023 |
| Linux | runc ol 9 | 4:1.1.9-1.el9 | [ELSA-2023-6380](https://patchblox.com/security/data/fix/linux/elsa-2023-6380.md) | Nov 11, 2023 |

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Data as of 2026-11-08T19:12:23Z 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

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