What is CVE-2026-18638?

CVE-2026-18638 is a medium-severity vulnerability in Rapid7 Velociraptor, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2026-08-11.

How severe is CVE-2026-18638?

Medium severity. CVSS v3 base score is 6.5 out of 10.

NULL pointer dereference in Rapid7 Velociraptor

CVE-2026-18638

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.

Published 2026-08-11 · last modified 2026-08-28.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.004 (32.6th percentile), scored 2026-09-26.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 32.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Rapid7 Velociraptor — versions 0

Weakness classification (CWE)

References

docs.velociraptor.app/announcements/advisories/cve-2026-18638/

Frequently asked questions

What is CVE-2026-18638?: CVE-2026-18638 is a medium-severity vulnerability in Rapid7 Velociraptor, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2026-08-11.
How severe is CVE-2026-18638?: Medium severity. CVSS v3 base score is 6.5 out of 10.