VendorsCiscoios15.5\(1\)sy1
Vulnerabilities

Cisco IOS 15.5\(1\)sy1

Ranked by severity, then by exploit likelihood. Click a CVE ID for its full record.

14CVEs
CVE-2020-3217
Cisco IOS, IOS XE, IOS XR, and NX-OS Software One Platform Kit Remote Code Execution Vulnerability
Published 2020-06-03 · Modified
8.8EPSS 0.011
CVE-2020-3228
Cisco IOS, IOS XE, and NX-OS Software Security Group Tag Exchange Protocol Denial of Service Vulnerability
Published 2020-06-03 · Modified
8.6EPSS 0.018
CVE-2023-20080
Cisco IOS and IOS XE Software IPv6 DHCP (DHCPv6) Relay and Server Denial of Service Vulnerability
Published 2023-03-23 · Modified
8.6EPSS 0.010
CVE-2024-20311
A vulnerability in the Locator ID Separation Protocol (LISP) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability is due to the incorrect handling of LISP packets. An attacker could exploit this vulnerability by sending a crafted LISP packet to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition. Note: This vulnerability could be exploited over either IPv4 or IPv6 transport.
Published 2024-03-27 · Analyzed
8.6EPSS 0.008
CVE-2026-20301
Cisco IOS Software and IOS XE Software Extensible Messaging Client Protocol Denial of Service Vulnerability
Published 2026-08-05 · Analyzed
8.6EPSS 0.006
CVE-2021-34699
Cisco IOS and IOS XE Software TrustSec CLI Parser Denial of Service Vulnerability
Published 2021-09-23 · Modified
7.7EPSS 0.012
CVE-2021-1620
Cisco IOS and IOS XE Software IKEv2 AutoReconnect Feature Denial of Service Vulnerability
Published 2021-09-23 · Analyzed
7.7EPSS 0.011
CVE-2025-20174
A vulnerability in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper error handling when parsing SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.  This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMP v2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMP v3, the attacker must have valid SNMP user credentials for the affected system.
Published 2025-02-05 · Analyzed
7.7EPSS 0.008
CVE-2025-20176
A vulnerability in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper error handling when parsing SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.  This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMP v2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMP v3, the attacker must have valid SNMP user credentials for the affected system.
Published 2025-02-05 · Analyzed
7.7EPSS 0.008
CVE-2024-20307
A vulnerability in the IKEv1 fragmentation code of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a heap overflow, resulting in an affected device reloading. This vulnerability exists because crafted, fragmented IKEv1 packets are not properly reassembled. An attacker could exploit this vulnerability by sending crafted UDP packets to an affected system. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Only traffic that is directed to the affected system can be used to exploit this vulnerability. This vulnerability can be triggered by IPv4 and IPv6 traffic.
Published 2024-03-27 · Analyzed
7.5EPSS 0.007
CVE-2024-20312
A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.
Published 2024-03-27 · Modified
7.4EPSS 0.003
CVE-2017-12228
A vulnerability in the Cisco Network Plug and Play application of Cisco IOS 12.4 through 15.6 and Cisco IOS XE 3.3 through 16.4 could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive data by using an invalid certificate. The vulnerability is due to insufficient certificate validation by the affected software. An attacker could exploit this vulnerability by supplying a crafted certificate to an affected device. A successful exploit could allow the attacker to conduct man-in-the-middle attacks to decrypt confidential information on user connections to the affected software. Cisco Bug IDs: CSCvc33171.
Published 2017-09-28 · Modified
5.9EPSS 0.010
CVE-2021-1377
Cisco IOS and IOS XE Software ARP Resource Management Exhaustion Denial of Service Vulnerability
Published 2021-03-24 · Modified
5.8EPSS 0.014
CVE-2019-1758
Cisco IOS Software Catalyst 6500 Series 802.1x Authentication Bypass Vulnerability
Published 2019-03-28 · Modified
4.7EPSS 0.006