CVE intelligence and bounded remediation
CVE-2026-6909 — ATutor is vulnerable to Reflected XSS in /install/upgrade.php endpoint
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.
- Severity
- Medium
- CVSS
- 5.1 (4.0)
- Published
- 2026-05-11
- CISA KEV
- Not currently listed
- Ecosystem
- javascript/npm
- Weaknesses
- CWE-79
Affected products
No browser-safe affected-product rows are available.
Matched remediation archetype
Cross-site scripting and unsafe browser output
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
- Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
- Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.
Remediate safely
- Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
- Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
- Update affected rendering components and add tests for every output context using inert sentinel markup.
Authoritative sources
Complete CVE record and remediation plan
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