CVE-2019-17498

In libssh2 v1.9.0 and earlier versions, the SSH_MSG_DISCONNECT logic in packet.c has an integer overflow in a bounds check, enabling an attacker to specify an arbitrary (out-of-bounds) offset for a subsequent memory read. A crafted SSH server may be able to disclose sensitive information or cause a denial of service condition on the client system when a user connects to the server.

This flaw needs a malicious MITM SSH server. When an application compiled with libssh2 connects to such a MITM SSH server, the server can trigger an integer overflow leading to an OOB read in the SSH_MSG_DISCONNECT logic. This can cause the application compiled with libssh2 to crash. This is strictly a client side crash and the SSH server may not be affected.

Also note that when a user connects to a malicious MITM server there is already a risk of disclosing password/keys irrespective of the flaw.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.