Vulnerability-Lookup

GHSA-CFCV-65JQ-76JW

Vulnerability from github – Published: 2026-06-09 06:31 – Updated: 2026-06-09 12:32

Details

The Custom Block Builder WordPress plugin before 4.3.0 does not consistently check the unfiltered_html capability across all paths that write to its block template code fields, allowing administrators on multisite installations (or single-site installs with DISALLOW_UNFILTERED_HTML defined) to inject arbitrary JavaScript that executes for any visitor of pages embedding the affected block.

Severity

3.5 (Low)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-8981"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-09T06:16:54Z",
    "severity": "LOW"
  },
  "details": "The Custom Block Builder  WordPress plugin before 4.3.0 does not consistently check the unfiltered_html capability across all paths that write to its block template code fields, allowing administrators on multisite installations (or single-site installs with DISALLOW_UNFILTERED_HTML defined) to inject arbitrary JavaScript that executes for any visitor of pages embedding the affected block.",
  "id": "GHSA-cfcv-65jq-76jw",
  "modified": "2026-06-09T12:32:03Z",
  "published": "2026-06-09T06:31:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-8981"
    },
    {
      "type": "WEB",
      "url": "https://wpscan.com/vulnerability/9815b0e6-e411-4a5c-9c63-30bad21da698"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-8981 (GCVE-0-2026-8981)

Vulnerability from cvelistv5 – Published: 2026-06-09 06:00 – Updated: 2026-06-09 10:32

Title

Lazy Blocks < 4.3.0 - Admin+ Stored XSS via Custom Block Frontend HTML

Summary

Severity

3.5 (Low)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-79 Cross-Site Scripting (XSS)
CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

WPScan

References

1 reference

URL	Tags
https://wpscan.com/vulnerability/9815b0e6-e411-4a…	exploitvdb-entrytechnical-description

Impacted products

1 product

Vendor	Product	Version
Unknown	Custom Block Builder	Affected: 0 , < 4.3.0 (semver)

Credits

Luca Jungnickel WPScan

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 3.5,
              "baseSeverity": "LOW",
              "confidentialityImpact": "LOW",
              "integrityImpact": "LOW",
              "privilegesRequired": "HIGH",
              "scope": "UNCHANGED",
              "userInteraction": "REQUIRED",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-8981",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-09T10:32:46.274624Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-79",
                "description": "CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-09T10:32:50.766Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Custom Block Builder",
          "vendor": "Unknown",
          "versions": [
            {
              "lessThan": "4.3.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Luca Jungnickel"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "WPScan"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The Custom Block Builder  WordPress plugin before 4.3.0 does not consistently check the unfiltered_html capability across all paths that write to its block template code fields, allowing administrators on multisite installations (or single-site installs with DISALLOW_UNFILTERED_HTML defined) to inject arbitrary JavaScript that executes for any visitor of pages embedding the affected block."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "CWE-79 Cross-Site Scripting (XSS)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-09T06:00:09.486Z",
        "orgId": "1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81",
        "shortName": "WPScan"
      },
      "references": [
        {
          "tags": [
            "exploit",
            "vdb-entry",
            "technical-description"
          ],
          "url": "https://wpscan.com/vulnerability/9815b0e6-e411-4a5c-9c63-30bad21da698/"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Lazy Blocks \u003c 4.3.0 - Admin+ Stored XSS via Custom Block Frontend HTML",
      "x_generator": {
        "engine": "WPScan CVE Generator"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1bfdd5d7-9bf6-4a53-96ea-42e2716d7a81",
    "assignerShortName": "WPScan",
    "cveId": "CVE-2026-8981",
    "datePublished": "2026-06-09T06:00:09.486Z",
    "dateReserved": "2026-05-19T13:11:53.990Z",
    "dateUpdated": "2026-06-09T10:32:50.766Z",
    "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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-CFCV-65JQ-76JW

CVE-2026-8981 (GCVE-0-2026-8981)

Tags

Sightings

Nomenclature