CVE-2020-3235Network attack vector

Authenticated device reload via crafted SNMP OIDs

Published Jun 3, 2020 · Updated Nov 15, 2024

Improper input validation in Cisco IOS on Catalyst 4500 switches allows remote authenticated users to reload devices via crafted SNMP packets. The SNMP subsystem insufficiently validates specific object identifiers associated with CISCO-POWER-ETHERNET-EXT-MIB, causing the switch to reload. Exploitation requires SNMP polling, a Power over Ethernet line-card module, and either a read-only community string or SNMPv3 credentials.

CVSS severity7.7
High
EPSS probability1.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Cisco IOS on Catalyst 4500 switches allows remote authenticated users to reload devices via crafted SNMP packets. The SNMP subsystem insufficiently validates specific object identifiers associated with CISCO-POWER-ETHERNET-EXT-MIB, causing the switch to reload. Exploitation requires SNMP polling, a Power over Ethernet line-card module, and either a read-only community string or SNMPv3 credentials.

The record

CVE
CVE-2020-3235
Published
Jun 3, 2020
Updated
Nov 15, 2024
Vendor
Cisco
Product
Cisco IOS
Classifications
CWE-118, CWE-20, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 3, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cisco · Cisco IOSversion=n/a

Published CVSS scores

7.7NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
6.3NISTAV:N/AC:M/Au:S/C:N/I:N/A:C
7.7Cisco Systems, Inc.CVSS:3.0/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-118Incorrect Access of Indexable Resource ('Range Error')
CWE-20Improper Input Validation
T1499.004Endpoint Denial of Service: Application 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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