CVE-2021-34737

published 2021-09-09

CVE-2021-34737: 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…

Priority P3 43 high 7.5 CVSS 3.1

AV N AC L PR N UI N S U C N I N A H

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.

Affected

5 ranges

Vendor	Product	Version range	Fixed in
cisco	cisco_ios_xr_software	—	—
cisco	ios_xr	< 7.3.2	7.3.2
cisco	ios_xr	—	—
cisco	ios_xr	>= 7.4.0 < 7.4.1	7.4.1
cisco	ios_xr	7.4.0 – 7.4.1	—

CVSS provenance

nvd v3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd v2.0 5.0 MEDIUM AV:N/AC:L/Au:N/C:N/I:N/A:P

vendor_cisco 5.8 MEDIUM

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