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Mozilla Foundation Security Advisory 2006-30

Title: Deleted object reference when designMode="on"
Impact: Critical
Date: May 2, 2006
Reporter: Martijn Wargers, Nick Mott, splices
Affects: Firefox 1.5

Fixed in: Firefox 1.5.0.3

Description

Martijn Wargers and Nick Mott each described crashes that were discovered to ultimately stem from the same root cause: attempting to use a deleted controller context when designMode was turned on. This generally results in crashing the browser, but in theory references to deleted objects can be abused to run malicious code.

"splices" reported the same crash at the fan site MozillaZine and on Bugtraq, incorrectly describing it as a buffer overflow.

Update (31 July 2006)

The advisory originally stated that older clients (Firefox 1.0.x and the Mozilla Suite 1.7.x) were unaffected. This is incorrect as demonstrated by the testcase MoBB#4 at the Browser Fun Blog. Those clients were already at risk from many other published vulnerabilities and should no longer be used.

Workaround

Temporarily disable JavaScript until you can upgrade to a fixed version.

References