CVE-2019-1859: Cisco Small Business Switches Secure Shell Certificate Authentication Bypass Vulnerability

Q: What is the severity of CVE-2019-1859?

The severity of CVE-2019-1859 is classified as high due to its potential impact on the SSH authentication process.

Q: How do I fix CVE-2019-1859?

To fix CVE-2019-1859, update your Cisco Small Business Switch to a firmware version that is not affected, specifically version 1.4.10.6 or later.

Q: Which software versions are affected by CVE-2019-1859?

CVE-2019-1859 currently affects Cisco SG200, SG300, SF200, SF300, and related models running firmware versions prior to 1.4.10.6.

Q: What can an attacker do if CVE-2019-1859 is exploited?

If exploited, an attacker could bypass client-side certificate authentication, reverting to password authentication, which increases the risk of unauthorized access.

Q: Is CVE-2019-1859 remote or local attack vector?

The CVE-2019-1859 vulnerability can potentially be exploited remotely, allowing attackers to access affected systems without physical presence.

Published May 3, 2019

Updated

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.

Affected Software

456 affected components

cisco Sg200-50 Firmware<1.4.10.6

cisco Sg200-50

cisco Sg200-50p Firmware<1.4.10.6

cisco Sg200-50p

cisco Sg200-50fp Firmware<1.4.10.6

cisco Sg200-50fp

cisco Sg200-26 Firmware<1.4.10.6

cisco Sg200-26

cisco Sg200-26p Firmware<1.4.10.6

cisco Sg200-26p

cisco Sg200-26fp Firmware<1.4.10.6

cisco Sg200-26fp

cisco Sg200-18 Firmware<1.4.10.6

cisco Sg200-18

cisco Sg200-10fp Firmware<1.4.10.6

cisco Sg200-10fp

cisco Sg200-08 Firmware<1.4.10.6

cisco Sg200-08

cisco Sg200-08p Firmware<1.4.10.6

cisco Sg200-08p

cisco Sf200-24 Firmware<1.4.10.6

cisco Sf200-24

cisco Sf200-24p Firmware<1.4.10.6

cisco Sf200-24p

cisco Sf200-24fp Firmware<1.4.10.6

cisco Sf200-24fp

cisco Sf200-48 Firmware<1.4.10.6

cisco Sf200-48

cisco Sf200-48p Firmware<1.4.10.6

cisco Sf200-48p

cisco Sf302-08pp Firmware<1.4.10.6

cisco Sf302-08pp

cisco Sf302-08mpp Firmware<1.4.10.6

cisco Sf302-08mpp

cisco Sg300-10pp Firmware<1.4.10.6

cisco Sg300-10pp

cisco Sg300-10mpp Firmware<1.4.10.6

cisco Sg300-10mpp

cisco Sf300-24pp Firmware<1.4.10.6

cisco Sf300-24pp

cisco Sf300-48pp Firmware<1.4.10.6

cisco Sf300-48pp

cisco Sg300-28pp Firmware<1.4.10.6

cisco Sg300-28pp

cisco Sf300-08 Firmware<1.4.10.6

cisco Sf300-08

cisco Sf300-48p Firmware<1.4.10.6

cisco Sf300-48p

cisco Sg300-10mp Firmware<1.4.10.6

cisco Sg300-10mp

cisco Sg300-10p Firmware<1.4.10.6

cisco Sg300-10p

cisco Sg300-10 Firmware<1.4.10.6

cisco Sg300-10

cisco Sg300-28p Firmware<1.4.10.6

cisco Sg300-28p

cisco Sf300-24p Firmware<1.4.10.6

cisco Sf300-24p

cisco Sf302-08mp Firmware<1.4.10.6

cisco Sf302-08mp

cisco Sg300-28 Firmware<1.4.10.6

cisco Sg300-28

cisco Sf300-48 Firmware<1.4.10.6

cisco Sf300-48

cisco Sg300-20 Firmware<1.4.10.6

cisco Sg300-20

cisco Sf302-08p Firmware<1.4.10.6

cisco Sf302-08p

cisco Sg300-52 Firmware<1.4.10.6

cisco Sg300-52

cisco Sf300-24 Firmware<1.4.10.6

cisco Sf300-24

cisco Sf302-08 Firmware<1.4.10.6

cisco Sf302-08

cisco Sf300-24mp Firmware<1.4.10.6

cisco Sf300-24mp

cisco Sg300-10sfp Firmware<1.4.10.6

cisco Sg300-10sfp

cisco Sg300-28mp Firmware<1.4.10.6

cisco Sg300-28mp

cisco Sg300-52p Firmware<1.4.10.6

cisco Sg300-52p

cisco Sg300-52mp Firmware<1.4.10.6

cisco Sg300-52mp

cisco Sg500-28mpp Firmware<1.4.10.6

cisco Sg500-28mpp

cisco Sg500-52mp Firmware<1.4.10.6

cisco Sg500-52mp

cisco Sg500xg-8f8t Firmware<1.4.10.6

cisco Sg500xg-8f8t

cisco Sf500-24 Firmware<1.4.10.6

cisco Sf500-24

cisco Sf500-24p Firmware<1.4.10.6

cisco Sf500-24p

cisco Sf500-48 Firmware<1.4.10.6

cisco Sf500-48

cisco Sf500-48p Firmware<1.4.10.6

cisco Sf500-48p

cisco Sg500-28 Firmware<1.4.10.6

cisco Sg500-28

cisco Sg500-28p Firmware<1.4.10.6

cisco Sg500-28p

cisco Sg500-52 Firmware<1.4.10.6

cisco Sg500-52

cisco Sg500-52p Firmware<1.4.10.6

cisco Sg500-52p

cisco Sg500x-24 Firmware<1.4.10.6

cisco Sg500x-24

cisco Sg500x-24p Firmware<1.4.10.6

cisco Sg500x-24p

cisco Sg500x-48 Firmware<1.4.10.6

cisco Sg500x-48

cisco Sg500x-48p Firmware<1.4.10.6

cisco Sg500x-48p

cisco Sg250x-24 Firmware<2.5.0.78

cisco Sg250x-24

cisco Sg250x-24p Firmware<2.5.0.78

cisco Sg250x-24p

cisco Sg250x-48 Firmware<2.5.0.78

cisco Sg250x-48

cisco Sg250x-48p Firmware<2.5.0.78

cisco Sg250x-48p

cisco Sg250-08 Firmware<2.5.0.78

cisco Sg250-08

cisco Sg250-08hp Firmware<2.5.0.78

cisco Sg250-08hp

cisco Sg250-10p Firmware<2.5.0.78

cisco Sg250-10p

cisco Sg250-18 Firmware<2.5.0.78

cisco Sg250-18

cisco Sg250-26 Firmware<2.5.0.78

cisco Sg250-26

cisco Sg250-26hp Firmware<2.5.0.78

cisco Sg250-26hp

cisco Sg250-26p Firmware<2.5.0.78

cisco Sg250-26p

cisco Sg250-50 Firmware<2.5.0.78

cisco Sg250-50

cisco Sg250-50hp Firmware<2.5.0.78

cisco Sg250-50hp

cisco Sg250-50p Firmware<2.5.0.78

cisco Sg250-50p

cisco Sf250-24 Firmware<2.5.0.78

cisco Sf250-24

cisco Sf250-24p Firmware<2.5.0.78

cisco Sf250-24p

cisco Sf250-48 Firmware<2.5.0.78

cisco Sf250-48

cisco Sf250-48hp Firmware<2.5.0.78

cisco Sf250-48hp

cisco Sg350-10 Firmware<2.5.0.78

cisco Sg350-10

cisco Sg350-10p Firmware<2.5.0.78

cisco Sg350-10p

cisco Sg350-10mp Firmware<2.5.0.78

cisco Sg350-10mp

cisco Sg355-10p Firmware<2.5.0.78

cisco Sg355-10p

cisco Sg350-28 Firmware<2.5.0.78

cisco Sg350-28

cisco Sg350-28p Firmware<2.5.0.78

cisco Sg350-28p

cisco Sg350-28mp Firmware<2.5.0.78

cisco Sg350-28mp

cisco Sf350-48 Firmware<2.5.0.78

cisco Sf350-48

cisco Sf350-48p Firmware<2.5.0.78

cisco Sf350-48p

cisco Sf350-48mp Firmware<2.5.0.78

cisco Sf350-48mp

cisco Sg350xg-2f10 Firmware<2.5.0.78

cisco Sg350xg-2f10

cisco Sg350xg-24f Firmware<2.5.0.78

cisco Sg350xg-24f

cisco Sg350xg-24t Firmware<2.5.0.78

cisco Sg350xg-24t

cisco Sg350xg-48t Firmware<2.5.0.78

cisco Sg350xg-48t

cisco Sg350x-24 Firmware<2.5.0.78

cisco Sg350x-24

cisco Sg350x-24p Firmware<2.5.0.78

cisco Sg350x-24p

cisco Sg350x-24mp Firmware<2.5.0.78

cisco Sg350x-24mp

cisco Sg350x-48 Firmware<2.5.0.78

cisco Sg350x-48

cisco Sg350x-48p Firmware<2.5.0.78

cisco Sg350x-48p

cisco Sg350x-48mp Firmware<2.5.0.78

cisco Sg350x-48mp

cisco Sx550x-16ft Firmware<2.5.0.78

cisco Sx550x-16ft

cisco Sx550x-24ft Firmware<2.5.0.78

cisco Sx550x-24ft

cisco Sx550x-12f Firmware<2.5.0.78

cisco Sx550x-12f

cisco Sx550x-24f Firmware<2.5.0.78

cisco Sx550x-24f

cisco Sx550x-24 Firmware<2.5.0.78

cisco Sx550x-24

cisco Sx550x-52 Firmware<2.5.0.78

cisco Sx550x-52

cisco Sg550x-24 Firmware<2.5.0.78

cisco Sg550x-24

cisco Sg550x-24p Firmware<2.5.0.78

cisco Sg550x-24p

cisco Sg550x-24mp Firmware<2.5.0.78

cisco Sg550x-24mp

cisco Sg550x-24mpp Firmware<2.5.0.78

cisco Sg550x-24mpp

cisco Sg550x-48 Firmware<2.5.0.78

cisco Sg550x-48

cisco Sg550x-48p Firmware<2.5.0.78

cisco Sg550x-48p

cisco Sg550x-48mp Firmware<2.5.0.78

cisco Sg550x-48mp

cisco Sf550x-24 Firmware<2.5.0.78

cisco Sf550x-24

cisco Sf550x-24p Firmware<2.5.0.78

cisco Sf550x-24p

cisco Sf550x-24mp Firmware<2.5.0.78

cisco Sf550x-24mp

cisco Sf550x-48 Firmware<2.5.0.78

cisco Sf550x-48

cisco Sf550x-48p Firmware<2.5.0.78

cisco Sf550x-48p

cisco Sf550x-48mp Firmware<2.5.0.78

cisco Sf550x-48mp

All of the following

cisco Sg200-50 Firmware<1.4.10.6

cisco Sg200-50

All of the following

cisco Sg200-50p Firmware<1.4.10.6

cisco Sg200-50p

All of the following

cisco Sg200-50fp Firmware<1.4.10.6

cisco Sg200-50fp

All of the following

cisco Sg200-26 Firmware<1.4.10.6

cisco Sg200-26

All of the following

cisco Sg200-26p Firmware<1.4.10.6

cisco Sg200-26p

All of the following

cisco Sg200-26fp Firmware<1.4.10.6

cisco Sg200-26fp

All of the following

cisco Sg200-18 Firmware<1.4.10.6

cisco Sg200-18

All of the following

cisco Sg200-10fp Firmware<1.4.10.6

cisco Sg200-10fp

All of the following

cisco Sg200-08 Firmware<1.4.10.6

cisco Sg200-08

All of the following

cisco Sg200-08p Firmware<1.4.10.6

cisco Sg200-08p

All of the following

cisco Sf200-24 Firmware<1.4.10.6

cisco Sf200-24

All of the following

cisco Sf200-24p Firmware<1.4.10.6

cisco Sf200-24p

All of the following

cisco Sf200-24fp Firmware<1.4.10.6

cisco Sf200-24fp

All of the following

cisco Sf200-48 Firmware<1.4.10.6

cisco Sf200-48

All of the following

cisco Sf200-48p Firmware<1.4.10.6

cisco Sf200-48p

All of the following

cisco Sf302-08pp Firmware<1.4.10.6

cisco Sf302-08pp

All of the following

cisco Sf302-08mpp Firmware<1.4.10.6

cisco Sf302-08mpp

All of the following

cisco Sg300-10pp Firmware<1.4.10.6

cisco Sg300-10pp

All of the following

cisco Sg300-10mpp Firmware<1.4.10.6

cisco Sg300-10mpp

All of the following

cisco Sf300-24pp Firmware<1.4.10.6

cisco Sf300-24pp

All of the following

cisco Sf300-48pp Firmware<1.4.10.6

cisco Sf300-48pp

All of the following

cisco Sg300-28pp Firmware<1.4.10.6

cisco Sg300-28pp

All of the following

cisco Sf300-08 Firmware<1.4.10.6

cisco Sf300-08

All of the following

cisco Sf300-48p Firmware<1.4.10.6

cisco Sf300-48p

All of the following

cisco Sg300-10mp Firmware<1.4.10.6

cisco Sg300-10mp

All of the following

cisco Sg300-10p Firmware<1.4.10.6

cisco Sg300-10p

All of the following

cisco Sg300-10 Firmware<1.4.10.6

cisco Sg300-10

All of the following

cisco Sg300-28p Firmware<1.4.10.6

cisco Sg300-28p

All of the following

cisco Sf300-24p Firmware<1.4.10.6

cisco Sf300-24p

All of the following

cisco Sf302-08mp Firmware<1.4.10.6

cisco Sf302-08mp

All of the following

cisco Sg300-28 Firmware<1.4.10.6

cisco Sg300-28

All of the following

cisco Sf300-48 Firmware<1.4.10.6

cisco Sf300-48

All of the following

cisco Sg300-20 Firmware<1.4.10.6

cisco Sg300-20

All of the following

cisco Sf302-08p Firmware<1.4.10.6

cisco Sf302-08p

All of the following

cisco Sg300-52 Firmware<1.4.10.6

cisco Sg300-52

All of the following

cisco Sf300-24 Firmware<1.4.10.6

cisco Sf300-24

All of the following

cisco Sf302-08 Firmware<1.4.10.6

cisco Sf302-08

All of the following

cisco Sf300-24mp Firmware<1.4.10.6

cisco Sf300-24mp

All of the following

cisco Sg300-10sfp Firmware<1.4.10.6

cisco Sg300-10sfp

All of the following

cisco Sg300-28mp Firmware<1.4.10.6

cisco Sg300-28mp

All of the following

cisco Sg300-52p Firmware<1.4.10.6

cisco Sg300-52p

All of the following

cisco Sg300-52mp Firmware<1.4.10.6

cisco Sg300-52mp

All of the following

cisco Sg500-28mpp Firmware<1.4.10.6

cisco Sg500-28mpp

All of the following

cisco Sg500-52mp Firmware<1.4.10.6

cisco Sg500-52mp

All of the following

cisco Sg500xg-8f8t Firmware<1.4.10.6

cisco Sg500xg-8f8t

All of the following

cisco Sf500-24 Firmware<1.4.10.6

cisco Sf500-24

All of the following

cisco Sf500-24p Firmware<1.4.10.6

cisco Sf500-24p

All of the following

cisco Sf500-48 Firmware<1.4.10.6

cisco Sf500-48

All of the following

cisco Sf500-48p Firmware<1.4.10.6

cisco Sf500-48p

All of the following

cisco Sg500-28 Firmware<1.4.10.6

cisco Sg500-28

All of the following

cisco Sg500-28p Firmware<1.4.10.6

cisco Sg500-28p

All of the following

cisco Sg500-52 Firmware<1.4.10.6

cisco Sg500-52

All of the following

cisco Sg500-52p Firmware<1.4.10.6

cisco Sg500-52p

All of the following

cisco Sg500x-24 Firmware<1.4.10.6

cisco Sg500x-24

All of the following

cisco Sg500x-24p Firmware<1.4.10.6

cisco Sg500x-24p

All of the following

cisco Sg500x-48 Firmware<1.4.10.6

cisco Sg500x-48

All of the following

cisco Sg500x-48p Firmware<1.4.10.6

cisco Sg500x-48p

All of the following

cisco Sg250x-24 Firmware<2.5.0.78

cisco Sg250x-24

All of the following

cisco Sg250x-24p Firmware<2.5.0.78

cisco Sg250x-24p

All of the following

cisco Sg250x-48 Firmware<2.5.0.78

cisco Sg250x-48

All of the following

cisco Sg250x-48p Firmware<2.5.0.78

cisco Sg250x-48p

All of the following

cisco Sg250-08 Firmware<2.5.0.78

cisco Sg250-08

All of the following

cisco Sg250-08hp Firmware<2.5.0.78

cisco Sg250-08hp

All of the following

cisco Sg250-10p Firmware<2.5.0.78

cisco Sg250-10p

All of the following

cisco Sg250-18 Firmware<2.5.0.78

cisco Sg250-18

All of the following

cisco Sg250-26 Firmware<2.5.0.78

cisco Sg250-26

All of the following

cisco Sg250-26hp Firmware<2.5.0.78

cisco Sg250-26hp

All of the following

cisco Sg250-26p Firmware<2.5.0.78

cisco Sg250-26p

All of the following

cisco Sg250-50 Firmware<2.5.0.78

cisco Sg250-50

All of the following

cisco Sg250-50hp Firmware<2.5.0.78

cisco Sg250-50hp

All of the following

cisco Sg250-50p Firmware<2.5.0.78

cisco Sg250-50p

All of the following

cisco Sf250-24 Firmware<2.5.0.78

cisco Sf250-24

All of the following

cisco Sf250-24p Firmware<2.5.0.78

cisco Sf250-24p

All of the following

cisco Sf250-48 Firmware<2.5.0.78

cisco Sf250-48

All of the following

cisco Sf250-48hp Firmware<2.5.0.78

cisco Sf250-48hp

All of the following

cisco Sg350-10 Firmware<2.5.0.78

cisco Sg350-10

All of the following

cisco Sg350-10p Firmware<2.5.0.78

cisco Sg350-10p

All of the following

cisco Sg350-10mp Firmware<2.5.0.78

cisco Sg350-10mp

All of the following

cisco Sg355-10p Firmware<2.5.0.78

cisco Sg355-10p

All of the following

cisco Sg350-28 Firmware<2.5.0.78

cisco Sg350-28

All of the following

cisco Sg350-28p Firmware<2.5.0.78

cisco Sg350-28p

All of the following

cisco Sg350-28mp Firmware<2.5.0.78

cisco Sg350-28mp

All of the following

cisco Sf350-48 Firmware<2.5.0.78

cisco Sf350-48

All of the following

cisco Sf350-48p Firmware<2.5.0.78

cisco Sf350-48p

All of the following

cisco Sf350-48mp Firmware<2.5.0.78

cisco Sf350-48mp

All of the following

cisco Sg350xg-2f10 Firmware<2.5.0.78

cisco Sg350xg-2f10

All of the following

cisco Sg350xg-24f Firmware<2.5.0.78

cisco Sg350xg-24f

All of the following

cisco Sg350xg-24t Firmware<2.5.0.78

cisco Sg350xg-24t

All of the following

cisco Sg350xg-48t Firmware<2.5.0.78

cisco Sg350xg-48t

All of the following

cisco Sg350x-24 Firmware<2.5.0.78

cisco Sg350x-24

All of the following

cisco Sg350x-24p Firmware<2.5.0.78

cisco Sg350x-24p

All of the following

cisco Sg350x-24mp Firmware<2.5.0.78

cisco Sg350x-24mp

All of the following

cisco Sg350x-48 Firmware<2.5.0.78

cisco Sg350x-48

All of the following

cisco Sg350x-48p Firmware<2.5.0.78

cisco Sg350x-48p

All of the following

cisco Sg350x-48mp Firmware<2.5.0.78

cisco Sg350x-48mp

All of the following

cisco Sx550x-16ft Firmware<2.5.0.78

cisco Sx550x-16ft

All of the following

cisco Sx550x-24ft Firmware<2.5.0.78

cisco Sx550x-24ft

All of the following

cisco Sx550x-12f Firmware<2.5.0.78

cisco Sx550x-12f

All of the following

cisco Sx550x-24f Firmware<2.5.0.78

cisco Sx550x-24f

All of the following

cisco Sx550x-24 Firmware<2.5.0.78

cisco Sx550x-24

All of the following

cisco Sx550x-52 Firmware<2.5.0.78

cisco Sx550x-52

All of the following

cisco Sg550x-24 Firmware<2.5.0.78

cisco Sg550x-24

All of the following

cisco Sg550x-24p Firmware<2.5.0.78

cisco Sg550x-24p

All of the following

cisco Sg550x-24mp Firmware<2.5.0.78

cisco Sg550x-24mp

All of the following

cisco Sg550x-24mpp Firmware<2.5.0.78

cisco Sg550x-24mpp

All of the following

cisco Sg550x-48 Firmware<2.5.0.78

cisco Sg550x-48

All of the following

cisco Sg550x-48p Firmware<2.5.0.78

cisco Sg550x-48p

All of the following

cisco Sg550x-48mp Firmware<2.5.0.78

cisco Sg550x-48mp

All of the following

cisco Sf550x-24 Firmware<2.5.0.78

cisco Sf550x-24

All of the following

cisco Sf550x-24p Firmware<2.5.0.78

cisco Sf550x-24p

All of the following

cisco Sf550x-24mp Firmware<2.5.0.78

cisco Sf550x-24mp

All of the following

cisco Sf550x-48 Firmware<2.5.0.78

cisco Sf550x-48

All of the following

cisco Sf550x-48p Firmware<2.5.0.78

cisco Sf550x-48p

All of the following

cisco Sf550x-48mp Firmware<2.5.0.78

cisco Sf550x-48mp

Event History

May 3, 2019

CVE Published

via MITRE·04:40 PM

Data Sourced

via MITRE·04:40 PM

DescriptionSeverityWeakness

Data Sourced

via NVD·05:29 PM

DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

What is the severity of CVE-2019-1859?

The severity of CVE-2019-1859 is classified as high due to its potential impact on the SSH authentication process.

How do I fix CVE-2019-1859?

To fix CVE-2019-1859, update your Cisco Small Business Switch to a firmware version that is not affected, specifically version 1.4.10.6 or later.

Which software versions are affected by CVE-2019-1859?

CVE-2019-1859 currently affects Cisco SG200, SG300, SF200, SF300, and related models running firmware versions prior to 1.4.10.6.

What can an attacker do if CVE-2019-1859 is exploited?

If exploited, an attacker could bypass client-side certificate authentication, reverting to password authentication, which increases the risk of unauthorized access.

Is CVE-2019-1859 remote or local attack vector?

The CVE-2019-1859 vulnerability can potentially be exploited remotely, allowing attackers to access affected systems without physical presence.

CVE-2019-1859: Cisco Small Business Switches Secure Shell Certificate Authentication Bypass Vulnerability

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What is the severity of CVE-2019-1859?

How do I fix CVE-2019-1859?

Which software versions are affected by CVE-2019-1859?

What can an attacker do if CVE-2019-1859 is exploited?

Is CVE-2019-1859 remote or local attack vector?

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