CVE-2026-42189

Russh: Pre-auth DoS via unbounded allocation in keyboard-interactive auth

Published May 8, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Russh is a Rust SSH client & server library. Prior to version 0.60.1, a pre-authentication denial-of-service vulnerability exists in the server's keyboard-interactive authentication handler. A malicious client can crash any russh-based server that implements keyboard-interactive auth (e.g., for 2FA/TOTP) with a single malformed packet, requiring no credentials. This issue has been patched in version 0.60.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-f5v4-2wr6-hqmg russh has pre-auth DoS via unbounded allocation in its keyboard-interactive auth handler
History
Type Values Removed Values Added
First Time appeared Russh Project
Russh Project russh
Warpgate Project
Warpgate Project warpgate
CPEs cpe:2.3:a:russh_project:russh:*:*:*:*:*:rust:*:*
cpe:2.3:a:warpgate_project:warpgate:*:*:*:*:*:*:*:*
Vendors & Products Russh Project
Russh Project russh
Warpgate Project
Warpgate Project warpgate
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. Prior to version 0.60.1, a pre-authentication denial-of-service vulnerability exists in the server's keyboard-interactive authentication handler. A malicious client can crash any russh-based server that implements keyboard-interactive auth (e.g., for 2FA/TOTP) with a single malformed packet, requiring no credentials. This issue has been patched in version 0.60.1.
Title Russh: Pre-auth DoS via unbounded allocation in keyboard-interactive auth
Weaknesses CWE-770
CWE-789
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 11, 2026, 2:23 PM
Reserved
Apr 25, 2026, 1:53 AM
Status
Analyzed
Published
May 8, 2026, 8:16 PM
Modified
Oct 26, 2026, 6:10 PM