On Fri, Mar 13, 2026 at 01:55:00PM +0100, Salvatore Bonaccorso wrote:
The following vulnerability was published for openssh.
CVE-2026-3497[0]:
| Vulnerability in the OpenSSH GSSAPI delta included in various Linux
| distributions. This vulnerability affects the GSSAPI patches added
| by various Linux distributions and does not affect the OpenSSH
| upstream project itself. The usage of sshpkt_disconnect() on an
| error, which does not terminate the process, allows an attacker to
| send an unexpected GSSAPI message type during the GSSAPI key
| exchange to the server, which will call the underlying function and
| continue the execution of the program without setting the related
| connection variables. As the variables are not initialized to NULL
| the code later accesses those uninitialized variables, accessing
| random memory, which could lead to undefined behavior. The
| recommended workaround is to use ssh_packet_disconnect() instead,
| which does terminate the process. The impact of the vulnerability
| depends heavily on the compiler flag hardening configuration.
For the record, most of this was introduced in 1:8.0p1-1, in which I
attempted to update to modern internal APIs by switching from
packet_disconnect to sshpkt_disconnect (rather than
ssh_packet_disconnect, which would have been more correct). Prior to
that, we were using packet_disconnect, which is a thin wrapper around
ssh_packet_disconnect and thus _does_ terminate the process.
There are still some uninitialized variables, so out of an abundance of
caution I'll initialize those as part of ELTS updates to stretch and
buster, but my guess is that the same vulnerability does not really
apply there - and indeed
https://deb.freexian.com/extended-lts/tracker/CVE-2026-3497 marks
stretch and buster as not-affected.
--
Colin Watson (he/him) [[email protected]]
