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Mozilla Foundation Security Advisory 2012-89

Title: defaultValue security checks not applied
Impact: Critical
Announced: October 11, 2012
Reporter: moz_bug_r_a4
Products: Firefox, Thunderbird, SeaMonkey

Fixed in: Firefox 16.0.1
  Firefox ESR 10.0.9
  Thunderbird 16.0.1
  Thunderbird ESR 10.0.9
  SeaMonkey 2.13.1


Mozilla security researcher moz_bug_r_a4 reported a regression where security wrappers are unwrapped without doing a security check in defaultValue(). This can allow for improper access to the Location object. In versions 15 and earlier of affected products, there was also the potential for arbitrary code execution.

Security researcher Gareth Heyes also blogged about a Firefox 16 only symptom that is fixed in the updated versions.