CVE-2026-20268

Cisco · IOS XE Software

An internal security review identified a memory buffer vulnerability in Cisco IOS XE Software that could allow an unauthenticated remote attacker to cause a denial of service on an affected device.

Executive summary

A memory buffer vulnerability in Cisco IOS XE Software allows an unauthenticated remote attacker to cause a denial of service condition.

Vulnerability

This issue is classified as CWE-119, involving the improper restriction of operations within the bounds of a memory buffer. An unauthenticated attacker can leverage this weakness to disrupt system stability and cause a denial of service.

Business impact

Exploitation of this vulnerability leads to device crashes, which can cause severe disruption to network traffic and business operations. With a CVSS score of 8.6, this flaw represents a significant risk to the availability of critical infrastructure components that rely on Cisco IOS XE.

Remediation

Immediate Action: Apply the vendor-provided security updates to all affected Cisco IOS XE systems as soon as possible.

Proactive Monitoring: Monitor system logs for memory-related errors or unexpected device reloads that may indicate an exploitation attempt.

Compensating Controls: Implement firewall rules or ACLs to limit exposure of the device management plane to known, trusted source IP addresses.

Exploitation status

Public Exploit Available: No (exploit_available: false)

Analyst recommendation

Organizations should treat this vulnerability as a high priority. Ensure that all affected devices are patched according to the guidance provided in the Cisco security advisory to maintain the integrity and availability of the network.