NVD

CVE-2021-34737 Detail

Modified

This vulnerability has been modified since it was last analyzed by the NVD. It is awaiting reanalysis which may result in further changes to the information provided.

Description

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.

Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score: 7.5 HIGH

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

Nist CVSS score does not match with CNA score

CNA: Cisco Systems, Inc.

Base Score: 5.8 MEDIUM

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

CVSS 2.0 Severity and Vector Strings:

National Institute of Standards and Technology

NIST: NVD

Base Score: 5.0 MEDIUM

Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:P)

References to Advisories, Solutions, and Tools

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Hyperlink	Resource
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU	Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-476	NULL Pointer Dereference	NIST Cisco Systems, Inc.

Known Affected Software Configurations Switch to CPE 2.2

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Change History

5 change records found show changes

Initial Analysis by NIST 9/22/2021 11:10:14 AM

Action	Type	Old Value	New Value
Added	CVSS V3.1		NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Added	CVSS V2		NIST (AV:N/AC:L/Au:N/C:N/I:N/A:P)
Added	CWE		NIST CWE-476
Added	CPE Configuration		Record truncated, showing 500 of 939 characters. View Entire Change Record AND OR cpe:2.3:o:cisco:ios_xr::::::::* versions up to (excluding) 7.3.2 cpe:2.3:o:cisco:ios_xr::::::::* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs540-12z20g-sys-a:-:::::::* cpe:2.3:h:cisco:ncs540-12z20g-sys-d:-:::::::* cpe:2.3:h:cisco:ncs540-24z8q2c-m:-:::::::* cpe:2.3:h:cisco:ncs540-24z8q2c-sys:-:::::::* cpe:2.3:h:cisco:ncs540-28z4c-sys-a:-:
Added	CPE Configuration		AND OR cpe:2.3:o:cisco:ios_xr::::::::* versions up to (excluding) 7.3.2 cpe:2.3:o:cisco:ios_xr::::::::* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_5001:-:::::::* cpe:2.3:h:cisco:ncs_5002:-:::::::* cpe:2.3:h:cisco:ncs_5011:-:::::::*
Added	CPE Configuration		Record truncated, showing 500 of 520 characters. View Entire Change Record AND OR cpe:2.3:o:cisco:ios_xr::::::::* versions up to (excluding) 7.3.2 cpe:2.3:o:cisco:ios_xr::::::::* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_5501:-:::::::* cpe:2.3:h:cisco:ncs_5501-se:-:::::::* cpe:2.3:h:cisco:ncs_5502:-:::::::* cpe:2.3:h:cisco:ncs_5502-se:-:::::::* cpe:2.3:h:cisco:ncs_5508:-:::::::* cpe:2.3:h:cisco:ncs_
Added	CPE Configuration		AND OR cpe:2.3:o:cisco:ios_xr::::::::* versions up to (excluding) 7.3.2 cpe:2.3:o:cisco:ios_xr::::::::* versions from (including) 7.4.0 up to (excluding) 7.4.1 OR cpe:2.3:h:cisco:ncs_560-4:-:::::::* cpe:2.3:h:cisco:ncs_560-7:-:::::::*
Added	CPE Configuration		Record truncated, showing 500 of 824 characters. View Entire Change Record AND OR cpe:2.3:o:cisco:ios_xr::::::::* versions up to (excluding) 7.3.2 cpe:2.3:o:cisco:ios_xr::::::::* versions from (including) 7.4.0 up to (including) 7.4.1 OR cpe:2.3:h:cisco:asr_9000v-v2:-:::::::* cpe:2.3:h:cisco:asr_9001:-:::::::* cpe:2.3:h:cisco:asr_9006:-:::::::* cpe:2.3:h:cisco:asr_9010:-:::::::* cpe:2.3:h:cisco:asr_9901:-:::::::* cpe:2.3:h:cisco:asr_99
Added	CPE Configuration		AND OR cpe:2.3:o:cisco:ios_xr::::::::* versions up to (excluding) 7.3.2 cpe:2.3:o:cisco:ios_xr::::::::* versions from (including) 7.4.0 up to (including) 7.4.1 OR cpe:2.3:h:cisco:ios_xrv_9000:-:::::::*
Changed	Reference Type	https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU No Types Assigned	https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU Vendor Advisory

Quick Info

CVE Dictionary Entry:
CVE-2021-34737
NVD Published Date:
09/09/2021
NVD Last Modified:
11/21/2024
Source:
Cisco Systems, Inc.

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Information Technology Laboratory

National Vulnerability Database

National Vulnerability Database

CVE-2021-34737 Detail

Description

Metrics

References to Advisories, Solutions, and Tools

Weakness Enumeration

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Change History

CVE Modified by CVE 11/21/2024 1:11:05 AM

CVE Modified by Cisco Systems, Inc. 5/14/2024 5:15:03 AM

CVE Modified by Cisco Systems, Inc. 11/06/2023 10:36:15 PM

Initial Analysis by NIST 9/22/2021 11:10:14 AM

CVE Modified by Cisco Systems, Inc. 9/09/2021 2:15:13 AM

Quick Info