Actively exploited in the wild
Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
Cisco - IOS XR · Listed in the CISA KEV since 2021-11-03. This indicates confirmed attacks in production environments.
Required action: Apply updates per vendor instructions.
CVE-2020-3566
HighCVSS 8.6KEVSummary
A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. This is due to insufficient queue management for IGMP packets.
Risk Assessment
Potential memory exhaustion leading to instability of other processes, including interior and exterior routing protocols.
Recommendation
Apply Cisco IOS XR software updates that address this vulnerability.
Other vulnerabilities in Cisco IOS XR Software
See all- CVE-2017-6731High
A vulnerability in Multicast Source Discovery Protocol (MSDP) ingress packet processing for Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the MSDP session to be unexpectedly reset, leading to a short denial of service (DoS) condition. The MSDP session will restart within a few seconds.
- CVE-2017-6728High
A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary code at the root privilege level on an affected system, due to Incorrect Permissions.
- CVE-2016-9205High
A vulnerability in the HTTP 2.0 request handling code of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Event Management Service daemon (emsd) to crash, resulting in a denial of service (DoS) condition.
- CVE-2020-3569HighActively exploited
Multiple vulnerabilities in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to immediately crash the IGMP process or cause memory exhaustion and eventual crash. This is due to incorrect handling of IGMP packets.
- CVE-2026-20280High
A vulnerability in Cisco IOS XR Software was discovered during an internal security review. It relates to improper checking or handling of exceptional conditions, classified as CWE-703.
- CVE-2026-20278High
A vulnerability in Cisco IOS XR Software was discovered during an internal security review. It relates to improper neutralization issues, classified as CWE-707.
- CVE-2026-20277High
A vulnerability in Cisco IOS XR Software was discovered during an internal security review. It relates to protection mechanism failure issues, classified as CWE-693.
- CVE-2026-20276High
A vulnerability in Cisco IOS XR Software was discovered during an internal security review. It relates to insufficient control flow management issues, classified as CWE-691.
- CVE-2026-20275High
A vulnerability in Cisco IOS XR Software was discovered during an internal security review. It relates to incorrect calculation issues, classified as CWE-682.
- CVE-2026-20074High
A vulnerability in the IS-IS multi-instance routing feature of Cisco IOS XR Software allows an unauthenticated, adjacent attacker to cause an unexpected restart of the IS-IS process. The issue is due to insufficient input validation of incoming IS-IS packets.
Original NVD description (English source)
A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. The vulnerability is due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. An attacker could exploit this vulnerability by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to cause memory exhaustion, resulting in instability of other processes. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address this vulnerability.