# CVE-2021-3997: systemd: A flaw was found in systemd

CVE-2021-3997 is fixed in 37 products on 1 platform, first by libnss-myhostname 245.4-4ubuntu3.15, released January 9, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-3997
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0174
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 9, 2022

## Description

A flaw was found in systemd. An uncontrolled recursion in systemd-tmpfiles may lead to a denial of service at boot time when too many nested directories are created in /tmp.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libnss-myhostname Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libnss-myhostname 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss-myhostname-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | libnss-mymachines Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libnss-mymachines 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss-mymachines-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | libnss-resolve Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libnss-resolve 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss-resolve-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | libnss-systemd Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libnss-systemd 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnss-systemd-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | libpam-systemd Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libpam-systemd 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libpam-systemd-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | libsystemd0 Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libsystemd0 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libsystemd0-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | libudev1 Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [libudev1 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libudev1-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd Debian 12.15 (bookworm) | 250.2-1 | [DEBIAN-CVE-2021-3997](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3997.md) | Aug 23, 2022 |
| Linux | systemd Debian 13.5 (trixie) | 250.2-1 | [DEBIAN-CVE-2021-3997](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3997.md) | Aug 23, 2022 |
| Linux | systemd Debian 14 | 250.2-1 | [DEBIAN-CVE-2021-3997](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3997.md) | Aug 23, 2022 |
| Linux | systemd Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-container Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd-container 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-container-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd-container amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-container-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-coredump Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd-coredump 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-coredump-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-debugsource amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-devel amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-journal-remote Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd-journal-remote 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-journal-remote-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd-journal-remote amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-journal-remote-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-libs amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-libs-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-networkd amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-networkd-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-oomd-defaults amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-pam amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-pam-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-resolved amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-resolved-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-rpm-macros amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-standalone-sysusers amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-standalone-sysusers-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-standalone-tmpfiles amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-standalone-tmpfiles-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-sysv Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd-sysv 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-sysv-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd-tests Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd-tests 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-tests-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd-tests amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-tests-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-timesyncd Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [systemd-timesyncd 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-systemd-timesyncd-245.4-4ubuntu3.15.md) | Jan 9, 2022 |
| Linux | systemd-udev amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | systemd-udev-debuginfo amzn 2023 | 252.4-1161.amzn2023.0.1 | [ALAS2023-2023-025](https://patchblox.com/security/data/fix/linux/alas2023-2023-025.md) | Feb 17, 2023 |
| Linux | udev Ubuntu 20.04 LTS (focal) | 245.4-4ubuntu3.15 | [udev 245.4-4ubuntu3.15](https://patchblox.com/security/data/fix/linux/ubuntu-focal-udev-245.4-4ubuntu3.15.md) | Jan 9, 2022 |

---

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