CVE-2026-66797: apache software foundation apache cloudstack Improper Access Control
Vulnerability summary
CVE-2026-66797 is a medium (CVSS 5.4) Improper Access Control vulnerability in apache software foundation apache cloudstack. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.5% of scored vulnerabilities.
Timeline
- 21-08-2026PublishedVulnerability first disclosed.
- 21-08-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST5.4MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
EPSS trend
Probability
0.46%
Chance of exploitation in the next 30 days
Percentile
39%
Versus all other CVEs
30-day change
+0.20 pp
From 0.26% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Apache1 product
- cloudstack≥ 4.15.0.0, < 4.20.3.1 | ≥ 4.21.0.0, < 4.22.1.1
Apache software foundation1 product
- apache cloudstack≥ 4.16.0.0, ≤ 4.20.3.0 | ≥ 4.21.0.0, ≤ 4.22.1.0
2 vendors · 2 products