You are here: Security Center > Mozilla Foundation Security Advisories > MFSA 2012-51
Mozilla Foundation Security Advisory 2012-51
Title: X-Frame-Options header ignored when
duplicated
Impact: Moderate
Announced: July 17, 2012
Reporter: Frédéric Buclin
Products: Firefox, Thunderbird, SeaMonkey
Fixed in: Firefox 14
Firefox ESR 10.0.6
Thunderbird 14
Thunderbird ESR 10.0.6
SeaMonkey 2.11
Description
Bugzilla developer Frédéric Buclin reported that the
"X-Frame-Options header is ignored when the value is duplicated,
for example X-Frame-Options: SAMEORIGIN, SAMEORIGIN. This
duplication occurs for unknown reasons on some websites and when it occurs
results in Mozilla browsers not being protected against possible clickjacking
attacks on those pages
