CVE-2026-40223 Denial of service in systemd
A local unprivileged user can cause a denial of service by triggering an assertion failure in systemd when specific unit configurations are active.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40223?
CVE-2026-40223 is a medium-severity denial of service vulnerability in Systemd Project Systemd, published on 10 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In systemd 258 before 260, a local unprivileged user can trigger an assert when a Delegate=yes and User=<unset> unit exists and is running.
Weakness: CWE-696
Which versions are affected by CVE-2026-40223?
It affects 1 product.
Products include Systemd Project Systemd.
How do I fix CVE-2026-40223?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-40223 being exploited?
There is no known exploitation of CVE-2026-40223 in the wild and no public exploit code.
Other vulnerabilities in Systemd Project Systemd
Sources
Also known as DEBIAN-CVE-2026-40223, GHSA-52rm-r39v-fwv9, GHSA-x4h8-rrrg-q78f.