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Mozilla Foundation Security Advisory 2014-07

XSLT stylesheets treated as styles in Content Security Policy

Announced
February 4, 2014
Reporter
Frederik Braun
Impact
Moderate
Products
Firefox, SeaMonkey
Fixed in
  • Firefox 27
  • SeaMonkey 2.24

Description

Mozilla security engineer Frederik Braun reported an issue where the implementation of Content Security Policy (CSP) is not in compliance with the specification. XSLT stylesheets must be subject to script-src directives but Mozilla's implementation of CSP treats them as styles. This could lead to unexpected script execution if the style-src directives were less restrictive than those for scripts.

In general this flaw cannot be exploited through email in the Seamonkey product because scripting is disabled in mail, but is potentially a risk in browser or browser-like contexts.

References