CVE-2026-42189

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

HIGH
7.5
CVSS Score
Published: May 8, 2026 at 07:49 PM UTC
Updated: October 26, 2026 at 06:10 PM UTC
3 products affected across 3 vendorsWarpgateRusshRussh

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.60.1
v < 0.60.1
Affected range stops below 0.60.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/Eugeny/russh/security/advisories/GHSA-f5v4-2wr6-hqmg
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/Eugeny/russh/releases/tag/v0.60.1

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-770CWE-789

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