A vulnerability in the Hot Standby Router Protocol (HSRP) subsystem of Cisco IOS and IOS XE Software could allow an unauthenticated, adjacent attacker to receive potentially sensitive information from an affected device. The vulnerability is due to insufficient memory initialization. An attacker could exploit this vulnerability by receiving HSRPv2 traffic from an adjacent HSRP member. A successful exploit could allow the attacker to receive potentially sensitive information from the adjacent device.

A vulnerability in the VLAN Trunking Protocol (VTP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to corrupt the internal VTP database on an affected device and cause a denial of service (DoS) condition. The vulnerability is due to a logic error in how the affected software handles a subset of VTP packets. An attacker could exploit this vulnerability by sending VTP packets in a sequence that triggers a timeout in the VTP message processing code of the affected software. A successful exploit could allow the attacker to impact the ability to create, modify, or delete VLANs and cause a DoS condition. There are workarounds that address this vulnerability. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS Software or Cisco IOS XE Software, are operating in VTP client mode or VTP server mode, and do not have a VTP domain name configured. The default configuration for Cisco devices that ar…

The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.2 through 3.17 contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities. The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP: Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. All devices that have enabled SNMP…

A vulnerability in a startup script of Cisco IOS XE Software could allow an unauthenticated attacker with physical access to the targeted system to execute arbitrary commands on the underlying operating system with the privileges of the root user. More Information: CSCuz06639 CSCuz42122. Known Affected Releases: 15.6(1.1)S 16.1.2 16.2.0 15.2(1)E. Known Fixed Releases: Denali-16.1.3 16.2(1.8) 16.1(2.61) 15.6(2)SP 15.6(2)S1 15.6(1)S2 15.5(3)S3a 15.5(3)S3 15.5(2)S4 15.5(1)S4 15.4(3)S6a 15.4(3)S6 15.3(3)S8a 15.3(3)S8 15.2(5)E 15.2(4)E3 15.2(3)E5 15.0(2)SQD3 15.0(1.9.2)SQD3 3.9(0)E.

A vulnerability in the web user interface of Cisco IOS XE 3.1 through 3.17 could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient resource handling by the affected software when the web user interface is under a high load. An attacker could exploit this vulnerability by sending a high number of requests to the web user interface of the affected software. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. To exploit this vulnerability, the attacker must have access to the management interface of the affected software, which is typically connected to a restricted management network. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, if the web user interface of the software is enabled. By default, the web user interface is not enabled. Cisco Bug IDs: CSCup70353.

Memory leak in the Smart Install client implementation in Cisco IOS 12.2 and 15.0 through 15.2 and IOS XE 3.2 through 3.8 allows remote attackers to cause a denial of service (memory consumption) via crafted image-list parameters, aka Bug ID CSCuy82367.

The DNS forwarder in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.15 allows remote attackers to obtain sensitive information from process memory or cause a denial of service (data corruption or device reload) via a crafted DNS response, aka Bug ID CSCup90532.

Cisco IOS XE 3.1 through 3.17 and 16.1 on 64-bit platforms allows remote attackers to cause a denial of service (data-structure corruption and device reload) via fragmented IPv4 packets, aka Bug ID CSCux66005.

Cisco IOS 12.2 and 15.0 through 15.3 and IOS XE 3.1 through 3.9 allow remote attackers to cause a denial of service (device restart) via a crafted IPv4 Multicast Source Discovery Protocol (MSDP) Source-Active (SA) message, aka Bug ID CSCud36767.

The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.