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Heap-based Buffer OverflowWeakness · CWE-122

CVE-2026-20185

HIGH · 7.7 CVSS v3.1 Published 2026-05-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This is an improper error handling vulnerability in the SNMP subsystem of Cisco SG350 and SG350X series switches. When parsing response data from a specifically crafted SNMP request, the device fails to handle an error condition properly, triggering an unexpected reload that causes denial of service. The attacker needs valid SNMP credentials (community string for v1/v2c or user credentials for v3).

MitigationRestrict SNMP access to trusted management IPs via ACLs, disable SNMP if not required, use SNMPv3 with strong authentication, and apply Cisco firmware updates when available. If SNMP is required, ensure community strings are changed from defaults and access is limited to administrative networks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm device model
    Identify the exact model number of the Cisco switch (e.g., SG350-28, SG350X-24, SG350X-48). This is typically visible on the physical device label, in the web UI under Device Info, or via CLI command 'show version'.
    Affected if The device is a Cisco SG350 or SG350X series switch.
  2. Determine if SNMP is enabled
    Check SNMP status via the web UI under SNMP > SNMP Settings, or via CLI using 'show snmp' or 'show running-config | include snmp'. SNMP must be enabled for this vulnerability to be exploitable.
    Affected if SNMP is enabled on the device (any version: v1, v2c, or v3).
  3. Identify SNMP version and configuration
    Review the SNMP configuration to determine which versions are active. In the web UI, check SNMP > SNMPv3 User or SNMP > SNMP Community. Via CLI, use 'show snmp group' and 'show snmp user'. Note whether v1/v2c community strings or SNMPv3 users are configured.
    Affected if SNMPv1, SNMPv2c, or SNMPv3 is configured and active.
  4. Check SNMP community strings and credentials
    If using SNMPv1/v2c, identify the configured community strings via 'show snmp community' or the web UI. If using SNMPv3, identify configured users via 'show snmp user'. The vulnerability requires an attacker to have valid credentials.
    Affected if Default or weak community strings are in use, or SNMPv3 credentials are present and accessible to untrusted users.
  5. Review SNMP access control
    Examine SNMP access lists or ACLs that restrict SNMP access. In the web UI, check under SNMP > SNMP Settings for allowed management stations. Via CLI, look for 'snmp-server community' with ACL references or 'snmp-server view' configurations.
    Affected if SNMP is open to unauthenticated or untrusted network segments (no IP-based access restriction).

You are affected if you have a Cisco SG350 or SG350X switch with SNMP enabled and an attacker can reach the device with valid SNMP credentials.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict SNMP access to trusted management IPs via ACLs, disable SNMP if not required, use SNMPv3 with strong authentication, and apply Cisco firmware updates when available. If SNMP is required, ensure community strings are changed from defaults and access is limited to administrative networks.

Have this fixed Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
27.0 hours of engineering $4,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-20185 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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