Vulnerability-Lookup

GHSA-Q9R6-5JWM-RMGP

Vulnerability from github – Published: 2026-10-16 18:34 – Updated: 2026-10-16 18:34

Details

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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.

Severity

3.7 (Low)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

6.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-111624"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-306"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-16T18:17:42Z",
    "severity": "MODERATE"
  },
  "details": "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can complete the SignalR negotiate step and receive refreshed notifications that disclose content keys, including unpublished content, and reveal editorial activity timing.",
  "id": "GHSA-q9r6-5jwm-rmgp",
  "modified": "2026-10-16T18:34:44Z",
  "published": "2026-10-16T18:34:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-4c5q-6c64-96j7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111624"
    },
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/commit/243e082479c777d0f585bbd2f8db571607767b22"
    },
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/commit/b4f6cfc9d0955f9d8443e68353db4a692e91bd94"
    },
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHub.cs#L9-L11"
    },
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHubUpdater.cs#L58"
    },
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/releases/tag/release-17.7.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/umbraco/Umbraco-CMS/releases/tag/release-18.2.1"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/umbraco-cms-before-17.7.1-and-18.2.1-missing-authorization-on-signalr-hubs"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-111624 (GCVE-0-2026-111624)

Vulnerability from cvelistv5 – Published: 2026-10-16 17:39 – Updated: 2026-10-16 17:39

Title

Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs

Summary

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

3.7 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CWE

CWE-306 - Missing Authentication for Critical Function

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 6430 records in the last 180 days details

References

8 references

URL	Tags
https://github.com/umbraco/Umbraco-CMS/security/a…	vendor-advisory
https://github.com/umbraco/Umbraco-CMS/blob/relea…	technical-description
https://github.com/umbraco/Umbraco-CMS/blob/relea…	technical-description
https://github.com/umbraco/Umbraco-CMS/commit/b4f…	patch
https://github.com/umbraco/Umbraco-CMS/commit/243…	patch
https://github.com/umbraco/Umbraco-CMS/releases/t…	release-notes
https://github.com/umbraco/Umbraco-CMS/releases/t…	release-notes
https://www.vulncheck.com/advisories/umbraco-cms-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
umbraco	Umbraco-CMS	Affected: 17.0.0 , < 17.7.1 (semver) Affected: 18.0.0 , < 18.2.1 (semver) cpe:2.3:a:umbraco:umbraco_cms:::::::: cpe:2.3:a:umbraco:umbraco_cms::::::::

Date Public

2026-10-06 00:00

Credits

lichoin

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:github/umbraco/Umbraco-CMS",
          "product": "Umbraco-CMS",
          "repo": "https://github.com/umbraco/Umbraco-CMS",
          "vendor": "umbraco",
          "versions": [
            {
              "lessThan": "17.7.1",
              "status": "affected",
              "version": "17.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "18.2.1",
              "status": "affected",
              "version": "18.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "17.7.1",
                  "versionStartIncluding": "17.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "18.2.1",
                  "versionStartIncluding": "18.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "lichoin"
        }
      ],
      "datePublic": "2026-10-06T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "NONE"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.7,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-306",
              "description": "Missing Authentication for Critical Function",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-16T17:39:00.093Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-4c5q-6c64-96j7)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-4c5q-6c64-96j7"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHub.cs#L9-L11"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/blob/release-18.2.0/src/Umbraco.Cms.Api.Management/Preview/PreviewHubUpdater.cs#L58"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/commit/b4f6cfc9d0955f9d8443e68353db4a692e91bd94"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/commit/243e082479c777d0f585bbd2f8db571607767b22"
        },
        {
          "name": "Umbraco-CMS release-18.2.1 Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/releases/tag/release-18.2.1"
        },
        {
          "name": "Umbraco-CMS release-17.7.1 Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/umbraco/Umbraco-CMS/releases/tag/release-17.7.1"
        },
        {
          "name": "VulnCheck Advisory: Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/umbraco-cms-before-17.7.1-and-18.2.1-missing-authorization-on-signalr-hubs"
        }
      ],
      "title": "Umbraco CMS before 17.7.1 and 18.2.1 Missing Authorization on SignalR Hubs",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-111624",
    "datePublished": "2026-10-16T17:39:00.093Z",
    "dateReserved": "2026-10-16T14:31:11.287Z",
    "dateUpdated": "2026-10-16T17:39:00.093Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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