Vulnerability Monitor

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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 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.

Published

2021-09-09T05:15:11.963

Last Modified

2024-11-21T06:11:05.107

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 5.8 (MEDIUM)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:N/A:P

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

10.0

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-476
  • Type: Primary
    CWE-476
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System cisco ios_xr < 7.3.2 Yes
Operating System cisco ios_xr ≤ 7.4.1 Yes
Hardware cisco asr_9000v-v2 - No
Hardware cisco asr_9001 - No
Hardware cisco asr_9006 - No
Hardware cisco asr_9010 - No
Hardware cisco asr_9901 - No
Hardware cisco asr_9902 - No
Hardware cisco asr_9903 - No
Hardware cisco asr_9904 - No
Hardware cisco asr_9906 - No
Hardware cisco asr_9910 - No
Hardware cisco asr_9912 - No
Hardware cisco asr_9922 - No
Operating System cisco ios_xr < 7.3.2 Yes
Operating System cisco ios_xr ≤ 7.4.1 Yes
Hardware cisco ios_xrv_9000 - No
Operating System cisco ios_xr < 7.3.2 Yes
Operating System cisco ios_xr < 7.4.1 Yes
Hardware cisco ncs540-12z20g-sys-a - No
Hardware cisco ncs540-12z20g-sys-d - No
Hardware cisco ncs540-24z8q2c-m - No
Hardware cisco ncs540-24z8q2c-sys - No
Hardware cisco ncs540-28z4c-sys-a - No
Hardware cisco ncs540-28z4c-sys-d - No
Hardware cisco ncs540-acc-sys - No
Hardware cisco ncs540x-12z16g-sys-a - No
Hardware cisco ncs540x-12z16g-sys-d - No
Hardware cisco ncs540x-16z4g8q2c-a - No
Hardware cisco ncs540x-16z4g8q2c-d - No
Hardware cisco ncs540x-acc-sys - No
Operating System cisco ios_xr < 7.3.2 Yes
Operating System cisco ios_xr < 7.4.1 Yes
Hardware cisco ncs_5001 - No
Hardware cisco ncs_5002 - No
Hardware cisco ncs_5011 - No
Operating System cisco ios_xr < 7.3.2 Yes
Operating System cisco ios_xr < 7.4.1 Yes
Hardware cisco ncs_560-4 - No
Hardware cisco ncs_560-7 - No
Operating System cisco ios_xr < 7.3.2 Yes
Operating System cisco ios_xr < 7.4.1 Yes
Hardware cisco ncs_5501 - No
Hardware cisco ncs_5501-se - No
Hardware cisco ncs_5502 - No
Hardware cisco ncs_5502-se - No
Hardware cisco ncs_5508 - No
Hardware cisco ncs_5516 - No
References