Red Hat Bugzilla – Bug 183680
CVE-2006-0040 DoS from large email
Last modified: 2015-02-17 10:08:36 EST
As seen here: http://lwn.net/Articles/174015/
About 7 weeks ago an automated mailing list spewed a large but valid email
containing a lot of URLS and other formatting. When this email is fed into
evolution the behaviour it causes leads evolution to expand dramatically in
size and eat vast amounts of CPU time. If you've got a lot of patience and
memory it is eventually rendered correctly (many minutes and many gigs)
The attack in question can be triggered with a large but valid plain text
email containing no unusual features. It is possible to perform the attack with
a somewhat smaller message than the one given but the one provided should
suffice for analysis and testing.
Worse, and the reason this becomes more than irritating is that evolution
tries to be smart when it is killed or dies. On restarting it will go to
great trouble to attempt to restart in the same position it died or was shut
down - which triggers the DoS again each time evolution is opened.
This bug was reported to vendor-sec January 18th, and acknowledged January
19th as CVE-2006-0040. A request for any follow up details was posted end
of February. No vendor has chosen to provide any more information which I
The email that triggered the original accidental discovery is available at
As the problem appears to come from gtkhtml it is likely that other gtkhtml
users may be similarly afflicted.
Block large text emails with many URLS using a filter rule
Ask your vendor awkward questions
or switch mailer
Have we looked at this at all?
No response from upstream either. I guess evolution is no longer maintained.
Can we please drop it for RHEL5 and ship something else ?
For what it's worth, I filed a bug upstream which has gotten little attention:
Should this be assigned to mbarnes ?
It seems there's finally some movement on this upstream, though it's more of a
workaround in Evolution than a direct fix for GtkHtml.
I'll get the patch into Rawhide for testing.
Sorry, the link was supposed to be:
Progress and a beginning but not a useful one. The perfect variant of this
attack can screw you totally in a good deal under 4MB of input.
Moving this to F9Target.
Final Freeze is in effect now. Security fixes almost certainly warrant a freeze
break, so in case you build a fix for this, mail release engineering as
described here: 
I think at this point the solution is to drop GtkHTML entirely and move
Evolution over to WebKit/GTK+. I've already started working on this and am
hoping it will happen this year, at least for /viewing/ emails. Editing is
Common Vulnerabilities and Exposures assigned an identifier CVE-2006-0040 to
the following vulnerability:
GNOME Evolution 18.104.22.168 and earlier allows remote attackers to cause a denial of service (CPU and memory consumption) via a text e-mail with a large number of URLs, possibly due to unknown problems in gtkhtml.
I imagine that somewhere in the last 5 years, between Fedora 9 and current Fedora, this has been fixed. As it did not affect RHEL5, and will not be fixed in RHEL4, I'm closing this bug.