High severity · published May 8, 2026
CVE-2025-66172
Apache CloudStack: Any user can attach a volume in their VMs from backups they should not have access to
8.1
CVSS
0.5%
EPSS
No
On KEV
Description
The CloudStack Backup plugin has an improper access logic in versions 4.21.0.0 and 4.22.0.0. Anyone with authenticated user-account access in CloudStack 4.21.0.0+ environments, where this plugin is enabled and have access to specific APIs can restore a volume from any other user's backups and attach the volume to their own VMs.
Backup plugin users using CloudStack 4.21.0.0+ are recommended to upgrade to CloudStack version 4.22.0.1, which fixes this issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 44% 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
4.21.0.0 through 4.22.0.0 · source: vendor
CL
Cloudstack · Apache
4.21.0.0 before 4.22.0.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-66172
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-66172
Mailing List
https://lists.apache.org/thread/n8mt5b7wkpysstb8w7rr9f02kc5cq2xm
Mailing List
http://www.openwall.com/lists/oss-security/2026/05/09/3
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