CVE-2019-5599 SACK Slowness (FreeBSD 12 using the RACK TCP Stack)

Shawn Webb shawn.webb at
Fri Jul 5 13:40:05 UTC 2019

On Wed, Jul 03, 2019 at 10:18:12AM -0700, Gordon Tetlow wrote:
> Sorry for the late response, only so many hours in the day.

Completely understood. Thanks for taking the time to respond!

> On Tue, Jun 18, 2019 at 08:06:55PM -0400, Shawn Webb wrote:
> > It appears that Netflix's advisory (as of this writing) does not
> > include a timeline of events. Would FreeBSD be able to provide its
> > event timeline with regards to CVE-2019-5599?
> I don't generally document a timeline of events from our side. This
> particular disclosure was a bit unusual as it wasn't external but
> instead was an internal FreeBSD developer the security team often works
> with. As such, our process was a bit out of sync with normal (as much as
> we have a normal with our current processes). All of that said, we got
> notice in early June, about 10 days before public disclosure.

Perhaps this might be a good time to start keeping records for future
vulnerability reports, regardless of source of disclosure.

Does FreeBSD publish its vulnerability response process documentation?
If not, would FreeBSD be open to such transparency?

> > Were any FreeBSD derivatives given advanced notice? If so, which ones?
> They were not. I would like to get to a point where we feel we could
> give some sort of heads up for downstream, but we aren't there yet.

Sounds good. Let me know how I can help. I'm at your service.


Shawn Webb
Cofounder / Security Engineer

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