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CVE-2026-42189

Russh denial of service

7.5 HIGHPublic exploitEPSS 0.76%
  1. Published8 May 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Russh< 0.60.1
Warpgate< 0.23.1

Remediation

Fixed in
Russh≥ 0.60.1
Warpgate≥ 0.23.1

References

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Frequently asked

Is CVE-2026-42189 being actively exploited?

CVE-2026-42189 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.76%.

How severe is CVE-2026-42189?

CVE-2026-42189 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.76% probability of exploitation.

Which products are affected by CVE-2026-42189?

Affected products include Russh, Warpgate.

How do I fix CVE-2026-42189?

Upgrade affected software to a fixed version, for example Russh 0.60.1, Warpgate 0.23.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-42189 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.