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CVE-2019-1859

Cisco Small Business Switches Secure Shell Certificate Authentication Bypass Vulnerability

7.2 High

A vulnerability in the Secure Shell (SSH) authentication process of Cisco Small Business Switches software could allow an attacker to bypass client-side certificate authentication and revert to password authentication. The vulnerability exists because OpenSSH mishandles the authentication process. An attacker could exploit this vulnerability by attempting to connect to the device via SSH. A successful exploit could allow the attacker to access the configuration as an administrative user if the default credentials are not changed. There are no workarounds available; however, if client-side certificate authentication is enabled, disable it and use strong password authentication. Client-side certificate authentication is disabled by default.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
High
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.84%Up 0.4 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 7.2

Cisco Small Business Switches Secure Shell Certificate Authentication Bypass Vulnerability

A vulnerability in the Secure Shell (SSH) authentication process of Cisco Small Business Switches software could allow an attacker to bypass client-side certificate authentication and revert to password authentication. The vulnerability exists because OpenSSH mishandles the authentication process. An attacker could exploit this vulnerability by attempting to connect to the device via SSH. A successful exploit could allow the attacker to access the configuration as an administrative user if the default credentials are not changed. There are no workarounds available; however, if client-side certificate authentication is enabled, disable it and use strong password authentication. Client-side certificate authentication is disabled by default.

Record
CVE-2019-1859
CVSS 3.0
7.2 HighCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-285
Updated
2026-11-02
EUVDEUVD-2019-10416 7.2

A vulnerability in the Secure Shell (SSH) authentication process of Cisco Small Business Switches software could allow an attacker to bypass client-side certificate authentication and revert to password authentication. The vulnerability exists because OpenSSH mishandles the authentication process. An attacker could exploit this vulnerability by attempting to connect to the device via SSH. A successful exploit could allow the attacker to access the configuration as an administrative user if the default credentials are not changed. There are no workarounds available; however, if client-side certificate authentication is enabled, disable it and use strong password authentication. Client-side certificate authentication is disabled by default.

Record
EUVD-2019-10416
CVSS 3.0
7.2 HighCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-vxf6-wwjr-wqh4 7.2

A vulnerability in the Secure Shell (SSH) authentication process of Cisco Small Business Switches...

A vulnerability in the Secure Shell (SSH) authentication process of Cisco Small Business Switches software could allow an attacker to bypass client-side certificate authentication and revert to password authentication. The vulnerability exists because OpenSSH mishandles the authentication process. An attacker could exploit this vulnerability by attempting to connect to the device via SSH. A successful exploit could allow the attacker to access the configuration as an administrative user if the default credentials are not changed. There are no workarounds available; however, if client-side certificate authentication is enabled, disable it and use strong password authentication. Client-side certificate authentication is disabled by default.

Record
GHSA-vxf6-wwjr-wqh4
CVSS 3.1
7.2 HighCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-285, CWE-295
Updated
2026-11-02
NVD 7.2

A vulnerability in the Secure Shell (SSH) authentication process of Cisco Small Business Switches software could allow an attacker to bypass client-side certificate authentication and revert to password authentication. The vulnerability exists because OpenSSH mishandles the authentication process. An attacker could exploit this vulnerability by attempting to connect to the device via SSH. A successful exploit could allow the attacker to access the configuration as an administrative user if the default credentials are not changed. There are no workarounds available; however, if client-side certificate authentication is enabled, disable it and use strong password authentication. Client-side certificate authentication is disabled by default.

Record
CVE-2019-1859
CVSS 3.1
7.2 HighCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 3.0
7.2 HighCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
6.5 MediumAV:N/AC:L/Au:S/C:P/I:P/A:P
Weakness
CWE-285, CWE-295
Updated
2026-11-02

Affected products

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History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2019-1859 is a high vulnerability (CVSS 7.2) in Cisco Small Business 200 Series Smart Switches, published May 3, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.84%, the 58th percentile. No source names a fixed version.

References

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