CVE-2026-46609: Umbraco is an ASP.NET CMS

Routine

MEDIUM 4.6UPGRADE

CVE-2026-46609 is a medium-severity flaw (CVSS 4.6) affecting umbraco cms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Umbraco is an ASP.NET CMS. From version 14.0.0 to before version 17.4.0, authenticated users are able to inject HTML into an input field, which is rendered in the confirmation dialog without proper output encoding. This issue has been patched in version 17.4.0.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.6 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-06-10
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: umbraco

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-10 17:16 UTCPublished CVE record published
2026-10-26 11:10 UTCUpdated Record last modified

umbraco umbraco cms UPGRADE

Affected: >= 14.0.0 and < 17.4.0

Fixed in: 17.4.0

Safe to downgrade to: a release before 14.0.0

1. Check installed version

apt-cache policy umbraco-cms || rpm -q umbraco-cms || umbraco-cms --version

2. UPGRADE to 17.4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade umbraco-cms

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade umbraco-cms

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 14.0.0 (Debian / Ubuntu)

apt-cache madison umbraco-cms sudo apt install umbraco-cms=<VERSION_BEFORE_14.0.0> sudo apt-mark hold umbraco-cms

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

dnf --showduplicates list umbraco-cms sudo dnf downgrade umbraco-cms-<VERSION_BEFORE_14.0.0> sudo dnf versionlock add umbraco-cms

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-2026-46609?

umbraco cms: upgrade to 17.4.0. Exact commands for each OS are on this page.

Is CVE-2026-46609 being exploited?

CVE-2026-46609 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-2026-46609 affect?

CVE-2026-46609 affects umbraco cms. Severity is medium (CVSS 4.6). Umbraco is an ASP.NET CMS. From version 14.0.0 to before version 17.4.0, authenticated users are able to inject HTML into an input field, which is rendered in the confirmation dialog without proper output encoding. This issue has been patch

How urgent is CVE-2026-46609?

Priority 17/100. No elevated risk signals yet.

Software pages

.NET vulnerabilities

Related CVEs

CVE-2026-46616 MEDIUM 5.4 UPGRADE Umbraco is an ASP.NET CMS

References

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