CVE-2026-66797

MEDIUM
Published Aug 21, 2026 Modified Aug 27, 2026 CWE-284

Description

Improper access control in CloudStack's annotation functionality allows unauthorized comment creation and disclosure. The addAnnotation and listAnnotation APIs perform an ownership check when an entity's UUID is specified, but fail to honor its result correctly. This lets any authenticated user write annotations to, and disclose existing annotations/comments on, an entity they don't own by simply supplying its UUID. This issue affects Apache CloudStack: from 4.15.0.0 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.

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CVSS v3.1 Score

5.4
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0026
Probability of exploitation
0.18%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-284 CWE-284

Affected Products

Vendor Product
apache cloudstack
apache cloudstack

References

Frequently Asked Questions

What is CVE-2026-66797? +
Improper access control in CloudStack's annotation functionality allows unauthorized comment creation and disclosure. The addAnnotation and listAnnotation APIs perform an ownership check when an entity's UUID is specified, but fail to honor its result correctly. This lets any authenticated user write annotations to, and disclose existing annotations/comments on, an entity they don't own by simply supplying its UUID. This issue affects Apache CloudStack: from 4.15.0.0 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. It has a CVSS v3.1 base score of 5.4 (MEDIUM).
How severe is CVE-2026-66797? +
CVE-2026-66797 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-66797? +
CVE-2026-66797 affects products from apache, specifically: cloudstack. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-66797? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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