In the fast-paced world of cybersecurity, staying updated on threats and vulnerabilities is crucial. One such alarming development is a high-severity zero-day vulnerability discovered in Cisco IOS and IOS XE Software – tracked as CVE-2025-20352. This flaw has already been exploited in attacks, making it a significant concern for all organizations with SNMP-enabled devices.
Understanding the Threat: A Look at Cisco Zero-Day Vulnerability
The vulnerability stems from a stack-based buffer overflow weakness in the Simple Network Management Protocol (SNMP) subsystem of affected IOS and IOS XE software. It potentially affects all devices with SNMP enabled, posing serious risks.

Impact and Potential Attacks
Lower-privileged attackers can cause Denial-of-Service (DoS) conditions on unpatched devices. On the other hand, higher-privileged attackers can seize complete control of systems running vulnerable Cisco IOS XE software by executing code as the root user.
Mitigation Measures and Patches
At present, there are no workarounds apart from applying the patches recently released by Cisco. However, for administrators unable to immediately upgrade vulnerable software, temporarily limiting SNMP access on affected systems to trusted users can mitigate the issue.
- Upgrade to the fixed software indicated in the advisory to fully remediate this vulnerability.
- Limit SNMP access to trusted users as a temporary measure.
Exploring Other Vulnerabilities Patched by Cisco
In addition to the zero-day vulnerability, Cisco patched 13 other security flaws in May. Among them, two have proof-of-concept exploit code available:
Cross-Site Scripting (XSS) and Denial-of-Service Vulnerabilities
The first vulnerability, CVE-2025-20240, is a reflected cross-site scripting (XSS) flaw that allows an unauthenticated, remote attacker to steal cookies from vulnerable devices.
Denial-of-Service Vulnerability
The second vulnerability, CVE-2025-20149, is a denial-of-service (DoS) vulnerability that can cause service disruptions.
Staying Ahead of Cybersecurity Threats
The evolving threat landscape necessitates constant vigilance and updates. Regularly patching your devices, limiting access to sensitive data, and educating employees about potential threats can help safeguard your network from cyberattacks.
Key Takeaways
- Keep your Cisco devices up-to-date to avoid zero-day vulnerabilities like CVE-2025-20352.
- Limit SNMP access as a temporary measure if immediate patching is not possible.
- Be aware of other vulnerabilities patched by Cisco, such as the reflected XSS and DoS flaws mentioned above.
- Adopt best practices for network security to stay ahead of cyber threats.
Stay protected and secure your organization’s network against potential cyberattacks. Keep abreast of the latest vulnerabilities and take necessary steps to safeguard your digital assets.



