CVE-2026-20185: Heap-based Buffer Overflow in Cisco Cisco Small Business Smart and Managed Switches
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco 350 Series Managed Switches (SG350) and Cisco 350X Series Stackable Managed Switches (SG350X) firmware could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper error handling when parsing response data for a specific SNMP request. An attacker could exploit this vulnerability by sending a specific SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. 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.
AI Analysis
Technical Summary
This vulnerability arises from improper error handling in the SNMP subsystem of specific Cisco Small Business Smart and Managed Switches firmware. An attacker with valid SNMP read-only or read-write community strings (for SNMPv1 or v2c) or valid SNMPv3 user credentials can send a specially crafted SNMP request that causes a heap-based buffer overflow. This overflow leads to an unexpected device reload, causing a denial of service condition. The vulnerability affects firmware versions 2.5.9.54 and 2.5.9.55 on Cisco SG350 and SG350X switches. The CVSS 3.1 base score is 7.7, reflecting network attack vector, low attack complexity, required privileges, no user interaction, scope change, no confidentiality or integrity impact, and high availability impact.
Potential Impact
Successful exploitation results in a denial of service condition by causing the affected device to reload unexpectedly. There is no direct confidentiality or integrity impact reported. The device unavailability could disrupt network operations relying on the affected switches.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, ensure SNMP community strings and user credentials are tightly controlled and monitored to limit access. Restrict SNMP access to trusted management networks only to reduce exposure. No official patch or workaround has been provided by Cisco at this time.
CVE-2026-20185: Heap-based Buffer Overflow in Cisco Cisco Small Business Smart and Managed Switches
Description
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco 350 Series Managed Switches (SG350) and Cisco 350X Series Stackable Managed Switches (SG350X) firmware could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper error handling when parsing response data for a specific SNMP request. An attacker could exploit this vulnerability by sending a specific SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. 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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability arises from improper error handling in the SNMP subsystem of specific Cisco Small Business Smart and Managed Switches firmware. An attacker with valid SNMP read-only or read-write community strings (for SNMPv1 or v2c) or valid SNMPv3 user credentials can send a specially crafted SNMP request that causes a heap-based buffer overflow. This overflow leads to an unexpected device reload, causing a denial of service condition. The vulnerability affects firmware versions 2.5.9.54 and 2.5.9.55 on Cisco SG350 and SG350X switches. The CVSS 3.1 base score is 7.7, reflecting network attack vector, low attack complexity, required privileges, no user interaction, scope change, no confidentiality or integrity impact, and high availability impact.
Potential Impact
Successful exploitation results in a denial of service condition by causing the affected device to reload unexpectedly. There is no direct confidentiality or integrity impact reported. The device unavailability could disrupt network operations relying on the affected switches.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, ensure SNMP community strings and user credentials are tightly controlled and monitored to limit access. Restrict SNMP access to trusted management networks only to reduce exposure. No official patch or workaround has been provided by Cisco at this time.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 2025-10-08T11:59:15.394Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69fb718ecbff5d86100fce0f
Added to database: 5/6/2026, 4:51:26 PM
Last enriched: 5/6/2026, 5:06:54 PM
Last updated: 5/7/2026, 8:11:54 AM
Views: 9
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