CVE intelligence and bounded remediation

CVE-2025-54571 — ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx

Medium CVSS 6.9

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. In versions 2.9.11 and below, an attacker can override the HTTP response’s Content-Type, which could lead to several issues depending on the HTTP scenario. For example, we have demonstrated the potential for XSS and arbitrary script source code disclosure in the latest version of mod_security2. This issue is fixed in version 2.9.12.

Severity
Medium
CVSS
6.9 (4.0)
Published
2025-08-06
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-252, CWE-79

Affected products

  • owasp / modsecurity

Matched remediation archetype

Cross-site scripting and unsafe browser output

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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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