[CIVN-2026-0227] SNMP Denial of Service Vulnerability in Cisco

By Published On: May 9, 2026

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SNMP Denial of Service Vulnerability in Cisco


Indian – Computer Emergency Response Team (https://www.cert-in.org.in)


Severity Rating: HIGH


Systems Affected


Cisco SG350 and SG350X Series Managed Switch Firmware Releases 2.5.9.54 or 2.5.9.55

SG350-28P Switches

SG350-28MP Switches

SG350-52P Switches

SG350-52MP Switches

SG350X Series Switches

Overview


A vulnerability has been reported in the Simple Network Management Protocol (SNMP) subsystem of Cisco 350 Series Managed Switches (SG350) and Cisco 350X Series Stackable Managed Switches (SG350X), which could allow an authenticated, remote attacker to cause a Denial of Service (DoS) condition on the affected system.


Target Audience:

All IT Administrator and individuals responsible for maintaining and updating software.


Risk Assessment:

High risk of data manipulation and service disruption.


Impact Assessment:

Potential impact on confidentiality, integrity and availability of system.


Description


A Denial of Service (DoS) vulnerability exists in the SNMP subsystem due to improper error handling while parsing response data for a specific SNMP request. A remote attacker could exploit this vulnerability by sending a specially crafted SNMP request to the affected device.


Successful exploitation of this vulnerability could allow an attacker to cause the device to reload unexpectedly, resulting in a denial-of-service condition.


Note: This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMPv2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMPv3, the attacker must have valid SNMP user credentials for the affected system.


Solution


Apply appropriate fix/patches as mentioned in Cisco Advisory:

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg350-snmp-dos-GEFZr2Tj



Vendor Information


Cisco

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg350-snmp-dos-GEFZr2Tj


References


Cisco

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg350-snmp-dos-GEFZr2Tj


CVE Name

CVE-2026-20185




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Thanks and Regards,

CERT-In


Incident Response Help Desk

e-mail: incident@cert-in.org.in

Phone: +91-11-22902657

Toll Free Number: 1800-11-4949

Toll Free Fax : 1800-11-6969

Web: http://www.cert-in.org.in

PGP Fingerprint: A768 083E 4475 5725 B81A A379 2156 C0C0 B620 D0B4

PGP Key information:

https://www.cert-in.org.in/s2cMainServlet?pageid=CONTACTUS


Postal address:

Indian Computer Emergency Response Team (CERT-In)

Ministry of Electronics and Information Technology

Government of India

Electronics Niketan

6, C.G.O. Complex

New Delhi-110 003

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