A vulnerability in the interactions between the DHCP and TFTP features for Cisco Small Business 300 Series (Sx300) Managed Switches could allow an unauthenticated, remote attacker to cause the device to become low on system memory, which in turn could lead to an unexpected reload of the device and result in a denial of service (DoS) condition on an affected device.

The vulnerability is due to a failure to free system memory when an unexpected DHCP request is received. An attacker could exploit this vulnerability by sending a crafted DHCP packet to the targeted device. A successful exploit could allow the attacker to cause an unexpected reload of the device. There are no workarounds that address this vulnerability.

This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-sb300sms-dhcp

The web-management GUI implementation on Cisco Small Business SG300 devices 1.4.1.x allows remote attackers to cause a denial of service (HTTPS outage) via crafted HTTPS requests, aka Bug ID CSCuw87174.

The Cisco Small Business 200 Series Smart Switch 1.2.7.76 and earlier, Small Business 300 Series Managed Switch 1.2.7.76 and earlier, and Small Business 500 Series Stackable Managed Switch 1.2.7.76 and earlier allow remote attackers to cause a denial of service (SSL/TLS layer outage) via malformed (1) SSH or (2) SSL packets, aka Bug ID CSCua30246.