A systemd security update has been released for Arch Linux.

ASA-202107-57: systemd: denial of service

Arch Linux Security Advisory ASA-202107-57
=========================================
Severity: Medium
Date : 2021-07-21
CVE-ID : CVE-2021-33910
Package : systemd
Type : denial of service
Remote : No
Link :   https://security.archlinux.org/AVG-2179

Summary
======
The package systemd before version 249.1-1 is vulnerable to denial of
service.

Resolution
=========
Upgrade to 249.1-1.

# pacman -Syu "systemd>$9.1-1"

The problem has been fixed upstream in version 249.1.

Workaround
=========
None.

Description
==========
A denial of service security issue has been found in systemd before
version 249.1. A local attacker who is able to mount a filesystem with
a very long path can crash systemd and the whole system through an
attacker-controlled alloca().

Impact
=====
A local unprivileged attacker who is able to mount a filesystem with a
very long path can crash systemd and therefore the whole system.

References
=========
  https://www.qualys.com/2021/07/20/cve-2021-33910/denial-of-service-systemd.txt
  https://www.qualys.com/2021/07/20/cve-2021-33910/cve-2021-33910-crasher.c
  https://bugzilla.redhat.com/show_bug.cgi?id70887
  https://github.com/systemd/systemd/pull/20256
  https://github.com/systemd/systemd/commit/441e0115646d54f080e5c3bb0ba477c892861ab9
  https://github.com/systemd/systemd-stable/commit/764b74113e36ac5219a4b82a05f311b5a92136ce
  https://security.archlinux.org/CVE-2021-33910