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Mozilla Foundation Security Advisory 2012-15

XSS with multiple Content Security Policy headers

Announced
March 13, 2012
Reporter
Mike
Impact
Moderate
Products
Firefox, Firefox ESR, SeaMonkey, Thunderbird, Thunderbird ESR
Fixed in
  • Firefox 11
  • Firefox ESR 10.0.3
  • SeaMonkey 2.8
  • Thunderbird 11
  • Thunderbird ESR 10.0.3

Description

Security Researcher Mike Brooks of Sitewatch reported that if multiple Content Security Policy (CSP) headers are present on a page, they have an additive effect page policy. Using carriage return line feed (CRLF) injection, a new CSP rule can be introduced which allows for cross-site scripting (XSS) on sites with a separate header injection vulnerability.

Firefox 3.6 and Thunderbird 3.1 are not affected by this vulnerability.

References