How severe is CVE-2026-42189?

CVE-2026-42189 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-42189 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42189?

CVE-2026-42189 primarily affects Russh Project Russh. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-42189?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42189 have an EU (EUVD) identifier?

Yes. CVE-2026-42189 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28822.

When was CVE-2026-42189 published?

CVE-2026-42189 was published on 2026-05-08 and last updated on 2026-06-17.

CVE-2026-42189

CVE-2026-42189 is a high-severity vulnerability in Russh Project Russh with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-28822
Weakness: CWE-770
Affected product: Russh Project Russh
Published: 2026-05-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-42189?: 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.
How severe is CVE-2026-42189?: CVE-2026-42189 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-42189 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42189?: CVE-2026-42189 primarily affects Russh Project Russh. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42189?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42189 have an EU (EUVD) identifier?: Yes. CVE-2026-42189 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28822.
When was CVE-2026-42189 published?: CVE-2026-42189 was published on 2026-05-08 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:russh_project:russh:*:*:*:*:*:rust:*:*
cpe:2.3:a:warpgate_project:warpgate:*:*:*:*:*:*:*:*

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