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CVE-2026-66797: Improper access control in CloudStack's annotation functionality allows unauthorized comment creation and disc

34
Routine
MEDIUM 5.4WATCHLISTUPGRADE

CVE-2026-66797 is a medium-severity flaw (CVSS 5.4) affecting cloudstack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 Apa

Why this priority

  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score5.4 (Medium)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededLow
User interactionNone
EPSS exploit chance0.5% (top 60%)
CISA exploited listNo
WeaknessCWE-284
Published2026-08-21
Last modified2026-10-16
Publisher (CNA): Apache Software Foundation · Vendor: apache

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Last updated 2026-10-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

apache cloudstack UPGRADE
Affected: >= 4.15.0.0 and < 4.20.3.1 · >= 4.21.0.0 and < 4.22.1.1
Fixed in: 4.20.3.1, 4.22.1.1
Safe to downgrade to: a release before 4.15.0.0
1. Check installed version
apt-cache policy cloudstack || rpm -q cloudstack || cloudstack --version
2. UPGRADE to 4.20.3.1 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade cloudstack
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade cloudstack
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 4.15.0.0 (Debian / Ubuntu)
apt-cache madison cloudstack sudo apt install cloudstack=<VERSION_BEFORE_4.15.0.0> sudo apt-mark hold cloudstack
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list cloudstack sudo dnf downgrade cloudstack-<VERSION_BEFORE_4.15.0.0> sudo dnf versionlock add cloudstack
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-66797?

cloudstack: upgrade to 4.20.3.1, 4.22.1.1. Exact commands for each OS are on this page.

Is CVE-2026-66797 being exploited?

CVE-2026-66797 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-66797 affect?

CVE-2026-66797 affects cloudstack. Severity is medium (CVSS 5.4). 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 h

How urgent is CVE-2026-66797?

Priority 34/100. On your watchlist

Related CVEs

References

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