CVE Intelligence
Low Authentication

CVE-2026-111624 — Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

Umbraco CMS before 17.7.1 and 18.2.1 contains a missing authorization vulnerability that allows unauthenticated clients to connect to the backoffice PreviewHub and BackofficeHub SignalR hubs. Attackers can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.

Published Oct 16, 2026 · Updated Oct 16, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: VulnCheck

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • No scoring signals.

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Umbraco
Umbraco Cms
CVSS base
3.7
Low · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Umbraco Umbraco Cms).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Umbraco Umbraco Cms ≥ 17.0.0 and < 17.7.1≥ 18.0.0 and < 18.2.1 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.3 CVSS 4.0 Medium — — disclosure@vulncheck.com via NIST National Vulnerability Database
6.3 CVSS 4.0 Medium — — VulnCheck via CVE Program (cve.org) e CISA ADP
3.7 CVSS 3.1 Low 2.2 1.4 disclosure@vulncheck.com via NIST National Vulnerability Database
3.7 CVSS 3.1 Low — — GitHub, Inc. via GitHub Security Advisories
3.7 CVSS 3.1 Low — — VulnCheck via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N (score shown at the top: disclosure@vulncheck.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-306 · Missing Authentication for Critical Function

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
web/proxy/WAF logsnetwork IDS/IPSauthentication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Received → Awaiting Analysis
    Oct 16, 2026 · NIST National Vulnerability Database
  • Affected products added · umbraco/umbraco-cms
    Oct 16, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 16, 2026
  • CVSS changed · 3.7
    Oct 16, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 16, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 16, 2026 · Alertas do Telegram
  • CVE published
    Oct 16, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 16, 2026 – Oct 16, 2026
  • 1× Official description updated · Oct 16, 2026 – Oct 16, 2026

References

10 on the record

Elsewhere on this site

Umbraco
every CVE for this vendor
Authentication
same class
CWE-306
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-69197 Umbraco: Delivery API leaks protected (Public Access) content through Content Picker / Multi-Node Tree Picker expansion 29d
  • CVE-2026-46609 Umbraco.Cms: XSS/HTML Injection in Umbraco Backoffice confirmation dialog Jun 10, 2026
  • CVE-2026-46616 Umbraco.Cms: Open Redirect Vulnerability in Surface Controllers Jun 10, 2026
  • CVE-2026-31832 Umbraco Backoffice API Allows Unauthorized Modification of Domain Data Mar 10, 2026
  • CVE-2026-31833 Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering Mar 10, 2026
  • CVE-2026-31834 Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks Mar 10, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-111624 is "Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs", rated Low. It affects Umbraco Cms (Umbraco); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.7 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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