Apache CloudStack: Any user can attach a volume in their VMs from backups they should not have access to

published 2026-05-08 6 mo ago modified 2026-10-07 33 d ago also EUVD-2025-209742

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

apache cloudstack 4.22.0.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 6 mo ago (2026-05-09)

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected products

Apache Software Foundation Apache CloudStack

Classification

Weakness

CWE-359 Exposure of Private Personal Information to an Unauthorized Actor

References

lists.apache.org /thread/n8mt5b7wkpysstb8w7rr9f02kc5cq2xm
vendor-advisory, mailing-list, third-party-advisory
openwall.com /lists/oss-security/2026/05/09/3
mailing-list, third-party-advisory

Sources

CVE List CVE-2025-66172
NVD CVE-2025-66172

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary