Companies relying on Cisco’s networking equipment now face a renewed urgency to safeguard their infrastructure. Cisco has acknowledged a critical security flaw in its widely used IOS and IOS XE operating systems, exposing devices to real-world attacks through the Simple Network Management Protocol (SNMP). This vulnerability has prompted Cisco to issue security patches, and organizations using impacted versions are urged to act promptly to reduce potential disruption. Given the scope of affected hardware—from enterprise switches to service provider routers—the implications for broader digital operations are substantial. Network reliability is at the forefront as organizations assess their exposure and plan mitigation steps.
Recent disclosures about vulnerabilities in Cisco IOS and IOS XE underline the persistent challenges network operators face when relying on widely deployed protocols like SNMP. Previous incidents have shown that even minor configuration oversights can lead to extensive exposure, although those earlier cases were less likely to involve confirmed, active exploitation. By contrast, the newly reported attacks targeting CVE-2025-20352 highlight the increasing sophistication and speed with which attackers leverage newly discovered flaws, demanding faster responses from both vendors and customers than has often been the case in other incidents.
What Does the New SNMP Vulnerability Mean for Network Security?
The identified flaw, labeled CVE-2025-20352, occurs in the SNMP subsystem of Cisco’s IOS and IOS XE software. Attackers with authorized, low-level accounts can exploit the issue to crash network devices, resulting in denial-of-service. With elevated privileges, malicious actors could execute their own code with root access, taking full control of affected Cisco IOS XE devices. Cisco has confirmed that these attacks have moved beyond research and are being used against targets in the field.
How Are Affected Devices and Products Identified?
The vulnerability affects any Cisco device with SNMP enabled that has not specifically excluded the affected object ID (OID). This encompasses all SNMP protocol versions, from v1 through v3. Notably, Meraki MS390 and Catalyst 9300 switches running on Meraki CS 17 or earlier releases are subject to this flaw, pending an update to IOS XE. According to Cisco, “All devices that have SNMP enabled and have not explicitly excluded the affected object ID (OID) should be considered vulnerable.”
What Immediate Steps Should Organizations Take?
While there are no known workarounds except for implementing the new software patches, organizations unable to upgrade immediately are advised to restrict SNMP access to trusted networks and users. However, Cisco cautions that these strategies merely reduce risk but do not address the underlying vulnerability. The company recommends administrators check their device configurations and SNMP status through command-line checks as a preliminary action. As Cisco states,
“The only completely effective mitigation is to apply the fixed software provided by Cisco,”
reinforcing the urgency of this update.
Beyond SNMP, the security release includes patches for 13 additional vulnerabilities, two of which are considered significant for risk assessment: a cross-site scripting bug and a local denial-of-service threat, both with public proof-of-concept exploits. Only IOS and IOS XE platforms are affected; other systems like IOS XR and NX-OS remain unaffected, narrowing the focus for administrators seeking to prioritize their responses.
“We have not identified any impact to Cisco IOS XR Software or Cisco NX-OS Software,”
Cisco’s advisory clarifies.
This incident again highlights the critical role vendor communication and fast patch adoption play in protecting networked environments. The ability for authenticated users—even with low privileges—to inflict denial-of-service or execute arbitrary code demonstrates the persistent risks in using legacy protocols like SNMP across large-scale infrastructure. For organizations operating significant numbers of Cisco devices, ongoing risk mitigation requires not only keeping current with patches but also regularly auditing network access and monitoring for abnormal activity. Understanding how protocol-level flaws translate into practical attacks helps organizations assess their own operational security and influences how they plan for future vulnerabilities.
