Vulnerability in Apache Cloudstack

CVE-2026-61398

Improper Encoding or Escaping of Output vulnerability in Apache CloudStack's UI while using Instance Reset Password functionality. This issue affects Apache CloudStack: from 4.15.1.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0. Users are recommended to upgrade to version 4.20.3.1 or 4.22.1.1 or later, which fixes the issue.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.006 (45.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-61398: held from 0.003 to 0.006.

EPSS over last 30 days · oldest: 0.003 · newest: 0.006 · change: +0.003

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-61398?
CVE-2026-61398 is a critical-severity vulnerability in Apache Cloudstack, classified under Improper Encoding or Escaping of Output. CVSS score: 9.1/10. Published 2026-08-21.
How severe is CVE-2026-61398?
Critical severity. CVSS v3 base score is 9.1 out of 10.