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Vulnerability record · CVE-2019-1859 · published 3 May 2019

CVE-2019-1859: Cisco sg200-50 firmware improper authorization vulnerability

Cisco · Sg200 50 Firmware

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.

7.2 CVSS 3.1 High EPSS 0.84% · top 43.6% CWE-285 · Improper authorizationCWE-295 · Improper certificate validation
7.2CVSS 3.1 base score, v2 6.5
0.84%EPSS exploitation probability, 30 days
NoNot in CISA KEV
114Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected products

114 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-scbv Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-scbv Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-1859), CISA KEV, FIRST EPSS (scores of 2026-10-03). This page is refreshed as NVD updates the record.