CVE-2026-18638 Velociraptor server crash via the SetPassword API
Authenticated users can crash the Velociraptor server by calling SetPassword with a non-existent username, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-18638?
CVE-2026-18638 is a medium-severity denial of service vulnerability in Rapid7 Velociraptor, published on 11 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Any authenticated Velociraptor user — including one holding only the readerrole — can terminate the entire server process with a single request, by calling SetPassword with a username that does not exist.
Which versions are affected by CVE-2026-18638?
How do I fix CVE-2026-18638?
Apply the vendor's patch.
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-2026-18638 being exploited?
There is no known exploitation of CVE-2026-18638 in the wild and no public exploit code.
Sources
Also known as GHSA-79v4-qf48-mh94.