Anon Proxy ServerApplication · Anonproxyserver

CVE-2025-41357

MEDIUM · 6.1 CVSS v3.1 Published 2026-03-31
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Reflected Cross-Site Scripting (XSS) vulnerability in Anon Proxy Server v0.104. This vulnerability allows an attacker to execute JavaScript code in the victim's browser by sending him/her a malicious URL. This vulnerability can be exploited to steal sensitive user data, such as session cookies, or to perform actions on behalf of the user. It affects 'host' parameter in '/diagdns.php' endpoint.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Reflected XSS vulnerability in the 'host' parameter of the /diagdns.php endpoint in Anon Proxy Server v0.104. User-supplied input in the host parameter is rendered without proper sanitization or output encoding, allowing injection of arbitrary JavaScript code that executes in victim's browser.

MitigationImplement proper input validation for the host parameter (allowlist valid hostname/IP formats) and ensure all output is HTML-encoded before rendering. Consider using security frameworks or built-in encoding functions specific to the application's language.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Anon Proxy ServerApplication
Affected:= 0.104

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Anon Proxy Server version
    Locate the installed Anon Proxy Server version by checking the application's about page, version file, or running 'anonproxyserver --version' or similar version command provided by the application.
    Affected if The installed version is exactly 0.104 (version 0.104)
  2. Verify diagdns.php endpoint exists
    Locate the diagdns.php file in the web server's document root or application directory. Common paths may include /var/www/html/, /www/, or the application's web directory. Search for the file named 'diagdns.php'.
    Affected if The file diagdns.php exists in the application web directory
  3. Inspect host parameter handling in source code
    Open diagdns.php in a text editor or view its source code. Locate the section that processes the 'host' parameter (typically via $_GET['host'] or $_POST['host']). Check if the value is directly echoed or rendered without HTML encoding (such as htmlspecialchars() or equivalent) or input validation.
    Affected if The host parameter value is output directly without htmlspecialchars(), htmlentities(), or similar encoding functions
  4. Check if endpoint accepts user input
    Send a request to /diagdns.php with a test value in the host parameter, for example: GET /diagdns.php?host=test. Examine the response to confirm the parameter value is reflected in the output.
    Affected if The host parameter value is reflected in the page response without encoding

If the installed version is 0.104 AND the diagdns.php endpoint exists AND the host parameter is processed without HTML encoding, the environment is affected by this reflected XSS vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper input validation for the host parameter (allowlist valid hostname/IP formats) and ensure all output is HTML-encoded before rendering. Consider using security frameworks or built-in encoding functions specific to the application's language.

Fix this in Anon Proxy Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-41357 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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