CVE-2017-6720

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2017-09-21 · updated 2026-06-17
Weakness: CWE-119

Description

A vulnerability in the Secure Shell (SSH) subsystem of Cisco Small Business Managed Switches software could allow an authenticated, remote attacker to cause a reload of the affected switch, resulting in a denial of service (DoS) condition. The vulnerability is due to improper processing of SSH connections. An attacker could exploit this vulnerability by logging in to an affected switch via SSH and sending a malicious SSH message. This vulnerability affects the following Cisco products when SSH is enabled: Small Business 300 Series Managed Switches, Small Business 500 Series Stackable Managed Switches, 350 Series Managed Switches, 350X Series Stackable Managed Switches, 550X Series Stackable Managed Switches, ESW2 Series Advanced Switches. Cisco Bug IDs: CSCvb48377.

Affected products

Cisco Esw2-350G-52 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Esw2-350G-52Dc Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Esw2-550X-48 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Esw2-550X-48Dc Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-08 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-24 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-24Mp Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-24P Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-24Pp Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-48 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-48P Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf300-48Pp Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf302-08 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf302-08Mp Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf302-08Mpp Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf302-08P Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf302-08Pp Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf350-48 Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf350-48Mp Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf350-48P Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf500-24 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf500-24P Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf500-48 Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf500-48P Firmware: before 1.4.8.06 — fixed in 1.4.8.06
Cisco Sf550X-24 Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf550X-24Mp Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf550X-24P Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf550X-48 Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf550X-48Mp Firmware: before 2.3.0.130 — fixed in 2.3.0.130
Cisco Sf550X-48P Firmware: before 2.3.0.130 — fixed in 2.3.0.130

How to fix

Upgrade to a fixed version: Cisco Esw2-350G-52 Firmware 1.4.8.06; Cisco Esw2-350G-52Dc Firmware 1.4.8.06; Cisco Esw2-550X-48 Firmware 1.4.8.06; Cisco Esw2-550X-48Dc Firmware 1.4.8.06; Cisco Sf300-08 Firmware 1.4.8.06; Cisco Sf300-24 Firmware 1.4.8.06; Cisco Sf300-24Mp Firmware 1.4.8.06; Cisco Sf300-24P Firmware 1.4.8.06; Cisco Sf300-24Pp Firmware 1.4.8.06; Cisco Sf300-48 Firmware 1.4.8.06; Cisco Sf300-48P Firmware 1.4.8.06; Cisco Sf300-48Pp Firmware 1.4.8.06. Check the vendor advisory for mitigations.

References

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