Security readout for executives and security teams
Plain-English summary
This Cisco flaw can let someone with valid SNMP access crash certain Catalyst 4500 Series switches, forcing a reload and disrupting network availability. It is not described as unauthenticated or data-stealing. Business urgency is highest where these switches support critical connectivity and SNMP is reachable beyond tightly controlled management systems.
Executive priority
Prioritize remediation for Catalyst 4500 switches supporting core, campus, or production connectivity. The main business risk is network downtime from a device reload. Treat this as high priority where SNMP is enabled and reachable, but not as evidence of active compromise without local telemetry.
Technical view
CVE-2020-3235 affects the SNMP subsystem in Cisco IOS and IOS XE Software on Catalyst 4500 Series Switches. Insufficient input validation of specific SNMP object identifiers can allow an authenticated remote attacker to send a crafted SNMP packet that reloads the device, causing denial of service. The bundle lists Cisco IOS 12.2(53)SG1 as affected.
Likely exposure
Exposure is likely limited to organizations running affected Cisco Catalyst 4500 Series switches with SNMP enabled. Attackers need the SNMP read-only community string for SNMPv2c or earlier, or valid SNMPv3 user credentials. Devices with broadly reachable SNMP management interfaces carry higher operational risk.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. Exploitation requires authenticated SNMP access and a crafted SNMP packet. The expected impact is availability loss through device reload, not confidentiality or integrity compromise based on the source bundle.
Researcher notes
The source bundle provides vulnerability mechanics, authentication requirements, CVSS 7.7, and affected platform context, but not complete fixed-version details. Avoid claiming broader Cisco platform exposure beyond the cited Catalyst 4500 IOS/IOS XE scope unless verified in the Cisco advisory.
Mitigation direction
- Check Cisco’s advisory for affected and fixed release guidance.
- Upgrade or remediate affected Catalyst 4500 devices per vendor guidance.
- Restrict SNMP reachability to authorized management systems only.
- Review SNMP community strings and SNMPv3 credentials for unnecessary access.
- Monitor affected devices for unexpected reloads and SNMP-related errors.
Validation and detection
- Inventory Catalyst 4500 Series switches and their IOS or IOS XE versions.
- Identify devices running the listed Cisco IOS 12.2(53)SG1 version.
- Confirm whether SNMP is enabled on each potentially affected device.
- Verify SNMP access is limited to trusted management hosts.
- Review logs for unexplained reloads around SNMP polling or management activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-118: Exact CWE lookup
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Open ATT&CK lookupCVE-2020-3235 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H3.14Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.7HighVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20200603 Cisco IOS and IOS XE Software Simple Network Management Protocol Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
- https://www.oracle.com/security-alerts/cpuoct2020.htmlCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incorrect Access of Indexable Resource ('Range Error')
Incorrect Access of Indexable Resource ('Range Error') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.