Mozilla Foundation Security Advisory 2007-09

Mozilla Foundation Security Advisory 2007-09
Title: Privilege escalation by setting img.src to javascript: URI
Impact: Critical
Announced: March 5, 2007
Reporter: moz_bug_r_a4
Products: Firefox 1.5.0.9/2.0.0.1, SeaMonkey 1.0.7

Fixed in: Firefox 2.0.0.2
Firefox 1.5.0.10
SeaMonkey 1.1.1
SeaMonkey 1.0.8
Description
moz_bug_r_a4 reports that the fix for MFSA 2006-72 in Firefox 1.5.0.9 and Firefox 2.0.0.1 introduced a regression that allows scripts from web content to execute arbitrary code by setting the src attribute of an IMG tag to a specially crafted javascript: URI.

The same regression also caused javascript: URIs in IMG tags to be executed even if JavaScript execution was disabled in the global preferences. This facet was noted by moz_bug_r_a4 and reported independently by Anbo Motohiko.

Thunderbird is not affected by this flaw as it will not execute javascript: URIs in IMG tags.
Workaround
Upgrade to a version containing the fix. Disabling JavaScript does not protect against this flaw.
References
CVE-2007-0994
https://bugzilla.mozilla.org/show_bug.cgi?id=368763
https://bugzilla.mozilla.org/show_bug.cgi?id=368655