CVE-2026-20185Network attack vector

Device reload via improper SNMP error handling

Published May 6, 2026 · Updated May 6, 2026

Heap-based buffer overflow in Cisco SG350 and SG350X firmware 2.5.9.54 and 2.5.9.55 allows remote authenticated users to reboot switches. The SNMP subsystem improperly handles errors while parsing response data for a specific SNMP request, triggering an unexpected device reload. Exploitation requires two or more enabled 60-watt PoE ports plus an SNMPv1/v2c community string or valid SNMPv3 credentials; the reload interrupts switching services.

CVSS severity7.7
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Cisco SG350 and SG350X firmware 2.5.9.54 and 2.5.9.55 allows remote authenticated users to reboot switches. The SNMP subsystem improperly handles errors while parsing response data for a specific SNMP request, triggering an unexpected device reload. Exploitation requires two or more enabled 60-watt PoE ports plus an SNMPv1/v2c community string or valid SNMPv3 credentials; the reload interrupts switching services.

The record

CVE
CVE-2026-20185
Published
May 6, 2026
Updated
May 6, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-122, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.7Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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