SB2021090914 - Denial of service in Cisco IOS XR DHCP implementation
Published: September 9, 2021
Security Bulletin ID
SB2021090914
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Adjecent network
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) NULL pointer dereference (CVE-ID: CVE-2021-34737)
CWE-ID: CWE-476 - NULL Pointer Dereference
CVSSv4: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error in the DHCP version 4 (DHCPv4) server feature of Cisco IOS XR Software. A remote non-authenticated attacker can send specially crafted DHCPv4 messages to the affected device, trigger a NULL pointer dereference error and crash the dhcpd process.
Remediation
Install update from vendor's website.