Vulnerabilities in Cisco IOS and IOS XE Software Permit Attackers to Run Code Remotely
Cisco has revealed a serious flaw in its popular IOS and IOS XE software that could give hackers the power to remotely execute code and crash devices or take over entire systems.
The vulnerability, which is based on the Simple Network Management Protocol (SNMP) subsystem, is caused by a stack overflow that an attacker can cause with a specifically constructed SNMP packet over IPv4 or IPv6 networks.
All SNMP versions are impacted by this problem, which has previously been exploited in the field, emphasizing how urgent it is that network managers take immediate action.
Two primary attack paths are made possible by the vulnerability. Armed with correct SNMPv3 credentials or SNMPv2c read-only community strings, a low-privileged, authenticated remote attacker may cause a denial-of-service (DoS) condition that would force impacted devices to reload and interfere with network operations.
Even more concerning is the possibility that a highly empowered attacker with administrative or privilege level 15 access may take over an entire system by running arbitrary code as the root user on iOS XE devices.
This was found during a Technical Assistance Center support case by Cisco’s Product Security Incident Response Team (PSIRT), and compromised local administrator credentials were followed by real-world attacks.
This vulnerability affects a wide variety of Cisco equipment, such as routers, switches, and access points that are crucial to enterprise infrastructures, running vulnerable versions of IOS or IOS XE with SNMP enabled.
Devices that haven’t specifically removed the impacted object ID (OID) are still vulnerable. Users of NX-OS and iOS XR software are somewhat relieved that these systems are not impacted.
There could be serious consequences: DoS assaults could stop vital services, and root-level code execution could allow malware to be deployed, data theft to occur, or networks to move laterally.
Many businesses unintentionally expose themselves by leaving default configurations in place due to the widespread use of SNMP for device monitoring.
Mitigations
Cisco stresses that while there aren’t any complete solutions, there are mitigations that can stop current attacks. Administrators should utilize the “show snmp host” CLI command to monitor and limit SNMP access to trusted users only.
One important step is to disable vulnerable OIDs by applying the limited view created by the “snmp-server view” command to community strings or SNMPv3 groups. To apply these modifications for Meraki cloud-managed switches, it is recommended to get in touch with support.
Cisco’s September 2025 Semiannual Security Advisory Bundled Publication now offers patches. The Cisco Software Checker tool allows users to identify fixed releases and confirm exposure.
Use CLI commands such as “show running-config | include snmp-server community” for v1/v2c or “show snmp user” for v3 to verify the status of SNMP.
Cisco advises updating robust software right away, cautioning that waiting could lead to more exploits. These vulnerabilities highlight the necessity of strict SNMP hardening and proactive patching as networks become more linked.
About The Author:
Yogesh Naager is a content marketer who specializes in the cybersecurity and B2B space. Besides writing for the News4Hackers blogs, he also writes for brands including Craw Security, Bytecode Security, and NASSCOM.
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