CVE-2026-23990: The Flux Operator is a Kubernetes CRD controller that manages the lifecycle of CNCF Flux CD and the ControlPla

Routine

MEDIUM 5.3WATCHLISTUPGRADE

CVE-2026-23990 is a medium-severity flaw (CVSS 5.3) affecting flux operator. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Flux Operator is a Kubernetes CRD controller that manages the lifecycle of CNCF Flux CD and the ControlPlane enterprise distribution. Starting in version 0.36.0 and prior to version 0.40.0, a privilege escalation vulnerability exists in the Flux Operator Web UI authentication code that allows an attacker to bypass Kubernetes RBAC impersonation and execute API requests with the operator's service account privileges. In order to be vulnerable,

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-269, CWE-862
Published	2026-01-21
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: control-plane

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-21 23:15 UTCPublished CVE record published
2026-06-17 10:22 UTCUpdated Record last modified

control-plane flux operator UPGRADE

Affected: >= 0.36.0 and < 0.40.0

Fixed in: 0.40.0

Safe to downgrade to: a release before 0.36.0

1. Check installed version

apt-cache policy flux-operator || rpm -q flux-operator || flux-operator --version

2. UPGRADE to 0.40.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade flux-operator

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade flux-operator

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 0.36.0 (Debian / Ubuntu)

apt-cache madison flux-operator sudo apt install flux-operator=<VERSION_BEFORE_0.36.0> sudo apt-mark hold flux-operator

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list flux-operator sudo dnf downgrade flux-operator-<VERSION_BEFORE_0.36.0> sudo dnf versionlock add flux-operator

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-2026-23990?

flux operator: upgrade to 0.40.0. Exact commands for each OS are on this page.

Is CVE-2026-23990 being exploited?

CVE-2026-23990 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-2026-23990 affect?

CVE-2026-23990 affects flux operator. Severity is medium (CVSS 5.3). The Flux Operator is a Kubernetes CRD controller that manages the lifecycle of CNCF Flux CD and the ControlPlane enterprise distribution. Starting in version 0.36.0 and prior to version 0.40.0, a privilege escalation vulnerability exists in

How urgent is CVE-2026-23990?

Priority 31/100. On your watchlist

Software pages

Kubernetes vulnerabilities

References

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