Cisco IOS and IOS XE SNMP Buffer Overflow Vulnerability

Historical catalog analysis: CISA added this entry on September 29, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2025-20352 is a stack-based buffer overflow vulnerability (CWE-121) located within the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE software. Depending on the attacker’s privilege level, the impact varies: low-privileged attackers could trigger a system reload resulting in a Denial of Service (DoS), while high-privileged attackers could execute arbitrary code with root-level permissions to gain full control of the affected system.

Exposure and applicability

This vulnerability is applicable to healthcare organizations utilizing Cisco networking hardware running affected versions of IOS or IOS XE. Because these operating systems often power core switches, routers, and gateways in clinical environments, a successful exploit could lead to significant operational disruptions. A DoS event causing a system reload could sever connectivity for electronic health record (EHR) access, medical device telemetry, and internal communications, directly impacting the continuity of patient care.

Remediation priorities

Our analysis suggests that healthcare IT and security leaders prioritize remediation based on the criticality of the network segment. We recommend the following priority sequence:

1. Critical Path Infrastructure: Prioritize patching or applying vendor-supplied mitigations for devices that support life-safety systems, emergency department connectivity, and core data center routing.
2. Management Plane Hardening: Review SNMP configurations to ensure that only authorized management stations can communicate with the SNMP subsystem, reducing the surface area available to potential attackers.
3. Privilege Audit: Evaluate the distribution of high-privileged accounts capable of interacting with the SNMP subsystem to limit the risk of Remote Code Execution (RCE).

How to validate remediation

To verify that exposure has been reduced, administrators should perform the following checks:
* Version Verification: Confirm that the running software version matches the patched releases specified in the official Cisco security advisory.
* Configuration Audit: Verify that SNMP access control lists (ACLs) are active and restricting traffic to known, trusted administrative IP addresses.
* Log Review: Monitor system logs for unexpected reloads or crashes associated with the SNMP process, which could indicate attempted exploitation or instability.

Limits and open questions

It remains unknown whether this vulnerability is currently being leveraged by ransomware campaigns. Furthermore, while patching reduces the likelihood of exploitation, it does not eliminate all risks associated with network management protocols. Organizations should note that CISA’s federal agency deadline of October 20, 2025, serves as a benchmark for urgency but is not a legal mandate for private healthcare providers. The effectiveness of any mitigation depends on the specific hardware model and software version in use; therefore, verification must be conducted against vendor-specific guidance.

Source and editorial note

CVE-2025-20352: Cisco IOS and IOS XE Software SNMP Denial of Service and Remote Code Execution Vulnerability · Source date: September 29, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: October 02, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: September 29, 2026 at 01:02 UTC.

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