CVE-2021-1623: Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers Simple Network Management Protocol Denial of Service Vulnerability

Severity: high (CVSS 7.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-23 · updated 2026-06-17
Weakness: CWE-399

Description

A vulnerability in the Simple Network Management Protocol (SNMP) punt handling function of Cisco cBR-8 Converged Broadband Routers could allow an authenticated, remote attacker to overload a device punt path, resulting in a denial of service (DoS) condition. This vulnerability is due to the punt path being overwhelmed by large quantities of SNMP requests. An attacker could exploit this vulnerability by sending a large number of SNMP requests to an affected device. A successful exploit could allow the attacker to overload the device punt path, resulting in a DoS condition.

Affected products

Cisco IOS XE: before 17.6.1a — fixed in 17.6.1a

How to fix

Upgrade to a fixed version: Cisco IOS XE 17.6.1a. Check the vendor advisory for mitigations.

References

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