Improper Input ValidationWeakness · CWE-20

CVE-2025-13826

HIGH · 8.2 CVSS v4.0 Published 2026-04-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
91/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Zervit's portable HTTP/web server is vulnerable to remote DoS attacks when a configuration reset request is made. The vulnerability is caused by inadequate validation of user-supplied input. An attacker can exploit this vulnerability by sending malicious requests. If the vulnerability is successfully exploited, the application can be made to stop responding, resulting in a DoS condition. It is possible to manually restart the application.

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 · moderate confidence

Zervit portable HTTP server contains a denial of service vulnerability triggered during configuration reset requests. The vulnerability results from inadequate validation of user-supplied input, allowing remote attackers to send malicious requests that cause the application to stop responding. Successful exploitation renders the service unavailable until manually restarted.

MitigationImplement strict input validation on all configuration reset request parameters, apply available vendor patches, and consider implementing request rate limiting to mitigate abuse. If no patch is available, consider network-level filtering of unauthenticated configuration endpoints.

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

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
Authentication
Y
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:D/RE:L/U:X

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 Zervit HTTP server is running
    Check for zervit.exe process running on the system, or verify ports 80/8080 are listening using 'netstat -ano | findstr :80' or similar tools
    Affected if Zervit HTTP server process is found running on the system
  2. Identify Zervit version
    Right-click on the zervit executable and select Properties > Details to view the version, or check any version information displayed at startup
    Affected if Unable to determine version or running an older release
  3. Verify configuration reset endpoint accessibility
    Send an HTTP request to common configuration reset paths (such as /reset, /config/reset, or /admin/reset) using curl or a browser
    Affected if Configuration reset endpoint responds without requiring authentication
  4. Test server responsiveness
    Send a basic HTTP GET request to the server root and verify normal response
    Affected if Server fails to respond or returns errors indicating it has stopped responding

User is affected if Zervit portable HTTP server is running and the configuration reset endpoint is exposed without authentication, allowing remote attackers to trigger the denial of service condition.

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 strict input validation on all configuration reset request parameters, apply available vendor patches, and consider implementing request rate limiting to mitigate abuse. If no patch is available, consider network-level filtering of unauthenticated configuration endpoints.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

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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-2025-13826 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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