CVE-2023-51385

Deeper analysis

The vulnerability is an OS command injection flaw, tracked as CWE-78, that affects the ssh client in OpenSSH versions prior to 9.6. It occurs when a username or hostname containing shell metacharacters is expanded via certain tokens, allowing the metacharacters to be interpreted by the shell rather than treated literally. An example trigger is a submodule entry inside an untrusted Git repository that supplies a malicious username or hostname.

An attacker can supply a crafted repository or configuration that causes the vulnerable ssh client to process the expansion during operations such as cloning or submodule handling. Successful exploitation yields limited command execution on the client system with no authentication required, corresponding to the CVSS vector AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

Public advisories and vendor patches direct users to upgrade to OpenSSH 9.6 or later; the referenced commit in the portable repository addresses the expansion handling, while distribution lists from Debian and Gentoo provide coordinated update guidance and package backports.

EPSS values have remained in a narrow band near 0.18 with no pronounced post-disclosure climb.