CVE-2021-34737 Cisco IOS XR Software DHCP Version 4 Server Denial of Service Vulnerability

2021-09-0905:01:30

CWE-476

cisco

www.cve.org

cisco

ios xr

dhcpv4

server

denial of service

vulnerability

CVSS3

5.8

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

EPSS

0.002

Percentile

51.9%

JSON

A vulnerability in the DHCP version 4 (DHCPv4) server feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to trigger a crash of the dhcpd process, resulting in a denial of service (DoS) condition. This vulnerability exists because certain DHCPv4 messages are improperly validated when they are processed by an affected device. An attacker could exploit this vulnerability by sending a malformed DHCPv4 message to an affected device. A successful exploit could allow the attacker to cause a NULL pointer dereference, resulting in a crash of the dhcpd process. While the dhcpd process is restarting, which may take up to approximately two minutes, DHCPv4 server services are unavailable on the affected device. This could temporarily prevent network access to clients that join the network during that time period. Note: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload.

CNA Affected

[
  {
    "product": "Cisco IOS XR Software",
    "vendor": "Cisco",
    "versions": [
      {
        "status": "affected",
        "version": "n/a"
      }
    ]
  }
]