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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-6909

MEDIUM · 5.1 CVSS v4.0 Published 2026-05-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
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
ATutor is vulnerable to Reflected XSS in /install/upgrade.php endpoint. An attacker can provide a specially crafted URL that, when opened, results in arbitrary JavaScript execution in the victim's browser. Product is no longer actively supported. Maintainers of this project were notified early about this vulnerability, but did not respond with the details of the vulnerability or vulnerable version range. Only version 2.2.4 was tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.

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

ATutor 2.2.4 contains a reflected cross-site scripting (XSS) vulnerability in the /install/upgrade.php endpoint. Attackers can craft malicious URLs containing JavaScript payloads that execute in victim browsers when the URL is opened. The vulnerable input is reflected back without proper sanitization or output encoding.

MitigationSince ATutor is unmaintained and the /install/upgrade.php endpoint should not be accessible in production, the recommended mitigation is to remove or restrict access to this file entirely, or deploy a web application firewall rule to filter malicious XSS patterns in URLs.

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
X
User interaction
A
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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:X/R:X/V:X/RE:X/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. Locate ATutor installation
    Search for ATutor files on the web server. Common locations include web root directories. Look for directories named 'ATutor' or files containing ATutor branding.
    Affected if ATutor is installed on the server
  2. Determine ATutor version
    Check for version information in typical ATutor files such as include/vitals.inc.php, about.php, or a CHANGELOG/README file within the ATutor directory.
    Affected if The installed version is 2.2.4 or falls within the affected range around 2.2.4
  3. Verify vulnerable endpoint exists
    Check if the file /install/upgrade.php exists in the ATutor web directory. Attempt to access it via HTTP request to confirm presence.
    Affected if The file /install/upgrade.php exists and is accessible via web request
  4. Confirm upgrade.php reflects user input without encoding
    Send a test request to /install/upgrade.php with a benign parameter value (such as ?test=<script>alert(1)</script>) and inspect the response to see if the script tags are returned unescaped in the HTML output.
    Affected if The response reflects the input parameter verbatim without HTML encoding
  5. Check if install directory is accessible in production
    Verify whether the /install/ directory and its contents are accessible from the internet by attempting to load /install/upgrade.php directly in a browser or via curl.
    Affected if The /install/upgrade.php endpoint is reachable from the network and returns the vulnerable page

A user is affected if ATutor version 2.2.4 (or nearby versions) is installed and the /install/upgrade.php endpoint is accessible, allowing reflected input to be returned without HTML encoding.

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

Since ATutor is unmaintained and the /install/upgrade.php endpoint should not be accessible in production, the recommended mitigation is to remove or restrict access to this file entirely, or deploy a web application firewall rule to filter malicious XSS patterns in URLs.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.

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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-2026-6909 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data