I notice this is a top story on eWeek this morning:
http://tinyurl.com/4gnc92

PV and the Slackware team will probably have a patch out soon, but if you
want to patch Firefox yourself using the Slackware source package, then be
aware that the Slackware source only repackages the official Firefox
binary. That means you need to download the 10M binary for 2.0.0.15,
not the actual source file (about 38M). Getting the right file from the
start could save someone some bandwidth ;)

Fixing up the official slackbuild is pretty straightforward. However,
in addition to updating the version number in the slackbuild, one
patch file also contains a hardcoded source number. AFAICT, it should be
fixed up as shown below (or similar):

$ cp mozilla-firefox-simple.diff.gz mozilla-firefox-simple.diff.gz.orig
$ zcat mozilla-firefox-simple.diff.gz.orig | sed 's/0.14/0.15/' | gzip \
>mozilla-firefox-simple.diff.gz

$ zcat mozilla-firefox-simple.diff.gz
--- ./firefox.orig 2007-05-15 06:47:30.000000000 -0500
+++ ./firefox 2007-06-01 18:15:02.000000000 -0500
@@ -92,8 +92,8 @@
#uncomment for debugging
#set -x

-moz_libdir=/usr/local/lib/firefox-2.0.0.15
-MRE_HOME=/usr/local/lib/mre/mre-2.0.0.15
+moz_libdir=/usr/lib/firefox-2.0.0.15
+MRE_HOME=/usr/lib/mre/mre-2.0.0.15

# Use run-mozilla.sh in the current dir if it exists
# If not, then start resolving symlinks until we find run-mozilla.sh

After fixing up the two files, the package should build.

--
Douglas Mayne