CISA flags Cisco IOS and IOS XE SNMP flaw (CVE-2025-20352) as actively exploited, warning of denial-of-service and remote code execution attacks. Organizations must prioritize fixes before October 20, 2025.
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has placed a critical vulnerability in Cisco IOS and IOS XE into its Known Exploited Vulnerabilities (KEV) catalog.
Tracked as CVE-2025-20352, the flaw affects the Simple Network Management Protocol (SNMP) subsystem and is reportedly being actively exploited in the wild.
Federal agencies have been given a remediation deadline of October 20, 2025, while industry counterparts across the private sector are cautioned to accelerate patch deployment to prevent disruption.
Critical Nature of CVE-2025-20352
This vulnerability stems from a stack-based buffer overflow present in specific SNMP configurations within Cisco IOS and IOS XE. An attacker with network access to the vulnerable subsystem can trigger different levels of impact depending on their privileges.
Low-privileged actors could exploit the flaw to cause denial-of-service conditions, forcing critical network equipment to reload and disrupting service availability.
More concerningly, highly privileged attackers could escalate to remote code execution, effectively gaining root access and seizing complete control of the affected device.
Such control enables adversaries to manipulate network traffic, disable defenses, or install persistent malware within trusted infrastructure.
Cisco has released mitigation measures and is urging customers to apply security updates immediately. The vulnerability is tied to CWE-121, a common buffer overflow weakness that has long been exploited by both state-aligned threat actors and financially motivated adversaries.
Broader Security Implications
While no specific ransomware campaigns have yet been linked to CVE-2025-20352, CISA’s inclusion of the flaw in the KEV catalog underscores the likelihood that it will be adopted into attacker playbooks.
Cisco IOS and IOS XE devices are cornerstones of enterprise and government networks, making them valuable targets for adversaries seeking either disruption or espionage opportunities.
Full compromise of such devices not only impairs availability but could enable adversaries to reroute, monitor, or exfiltrate sensitive data.
Past campaigns have demonstrated that once attackers gain access to network infrastructure, they can pivot deeper into organizational environments to impact critical applications, cloud workloads, and identity systems.
Exploiting this particular flaw could therefore serve as a launchpad for broader ransomware or nation-state operations.
What Organizations Should Do
CISA has directed federal agencies to update affected systems and to ensure compliance with Binding Operational Directive 22-01, which prioritizes patching of known exploited vulnerabilities.
For organizations outside the federal domain, the KEV catalog should similarly serve as a priority list for patch management.
Beyond patching Cisco devices, administrators are advised to audit existing SNMP configurations, disable unnecessary services, and monitor logs for unusual traffic patterns that may indicate exploit attempts.
The active exploitation of CVE-2025-20352 highlights the persistent targeting of core networking technologies and reinforces CISA’s guidance that organizations must treat KEV-designated flaws with urgency.
In the coming weeks, this vulnerability is expected to become a focal point for attackers, making rapid remediation essential.
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