CVE-2026-48108
Russh: SSH identification parsing accepted non-canonical client banners and did not bound pre-banner input
Description
Russh is a Rust SSH client & server library. From version 0.34.0-beta.1 to before version 0.61.0, russh did not enforce the SSH identification-string rules as deliberately as OpenSSH. In particular, the server-side identification reader used the same permissive path as the client, allowing pre-banner lines from clients, and the reader did not enforce a bounded number of pre-banner lines. For a library server built on russh, this could allow a remote peer to hold connection setup resources in the cleartext pre-authentication phase with malformed identification input that should have been rejected early. This issue has been patched in version 0.61.0.
How to fix CVE-2026-48108
To remediate CVE-2026-48108, upgrade the affected package to a fixed version below.
- —upgrade to 0.61.0 or later
- —no fix listed
Is CVE-2026-48108 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-48108.
Affected packages (2)
- >= 0.34.0-beta.1, < 0.61.0
- from 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |