CVE-2026-48108

Russh: SSH identification parsing accepted non-canonical client banners and did not bound pre-banner input

Published Jun 10, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-76r6-x97p-67vr Russh: SSH identification parsing accepted non-canonical client banners and did not bound pre-banner input
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Eugeny
Eugeny russh
Vendors & Products Eugeny
Eugeny russh
Type Values Removed Values Added
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.
Title Russh: SSH identification parsing accepted non-canonical client banners and did not bound pre-banner input
Weaknesses CWE-20
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jun 11, 2026, 1:50 PM
Reserved
May 20, 2026, 6:46 PM
Status
Deferred
Published
Jun 10, 2026, 10:17 PM
Modified
Jul 23, 2026, 9:10 AM