Medium severity · published Aug 21, 2026
CVE-2026-61399
Apache CloudStack: Cross-Site Scripting (XSS) Vulnerability in Lock User Function in UI
4.8
CVSS
0.5%
EPSS
No
On KEV
Description
Improper Encoding or Escaping of Output vulnerability in Apache CloudStack's UI while using Lock User Functionality.
This issue affects Apache CloudStack: from 4.20.0.0 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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
Apache CloudStack · Apache Software Foundation
4.20.0.0 through 4.20.3.0; 4.21.0.0 through 4.22.1.0 · source: vendor
CL
Cloudstack · Apache
4.20.0.0 before 4.20.3.1; 4.21.0.0 before 4.22.1.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-61399
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-61399
Mailing List
https://lists.apache.org/thread/g6cwddtjrwbh1d56wjz4cfp3fzfm4kbc
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