Security readout for executives and security teams
Plain-English summary
CVE-2020-3510 is a high-severity denial-of-service issue in Cisco IOS XE on Catalyst 9200 Series switches. An unauthenticated remote attacker can trigger a reload by crashing the iosd process through malformed DNS requests handled by Umbrella Connector. The documented impact is network disruption, not data theft.
Executive priority
Prioritize remediation for Catalyst 9200 switches in production, branch, campus, or high-availability paths. The risk is service interruption from remote unauthenticated traffic, so business urgency depends on whether affected switch interfaces are reachable from untrusted networks.
Technical view
The flaw is in Umbrella Connector DNS request parsing and is attributed to insufficient error handling, mapped to CWE-388. The CVSS 3.0 score is 8.6 with network attack vector, low complexity, no privileges, no user interaction, and high availability impact. Sources identify Cisco IOS XE Software on Catalyst 9200 Series switches.
Likely exposure
Exposure is most likely where Cisco Catalyst 9200 Series switches run affected IOS XE Software and have Umbrella Connector client interfaces reachable by untrusted systems. The bundle does not provide affected version ranges or configuration prerequisites beyond the named component and platform.
Exploitation context
The provided sources describe unauthenticated remote denial of service via malicious DNS requests. CISA KEV status is false in the bundle, and no cited source here confirms active exploitation. Treat exploitation evidence as not established, not disproven.
Researcher notes
The source bundle is specific about impact and attack class but incomplete on fixed releases, exact vulnerable IOS XE versions, and workarounds. Do not assume broader Cisco platforms are affected without vendor evidence. Validation should focus on platform, IOS XE release, Umbrella Connector use, and network reachability.
Mitigation direction
- Check Cisco’s advisory for fixed or recommended IOS XE releases.
- Prioritize affected Catalyst 9200 switches supporting critical network paths.
- Limit untrusted reachability to Umbrella Connector client interfaces where feasible.
- Monitor for unexpected iosd crashes or switch reloads.
- Follow Cisco operational guidance before changing Umbrella Connector configuration.
Validation and detection
- Inventory Catalyst 9200 Series switches and current IOS XE versions.
- Determine whether Umbrella Connector is enabled on each device.
- Map which networks can send DNS traffic to relevant client interfaces.
- Review logs for iosd crashes, reloads, or repeated DNS parsing errors.
- Confirm remediation status against Cisco’s advisory, not only CVE metadata.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-388: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-3510 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
- 8.6 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/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:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.6HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20200924 Cisco IOS XE Software for Catalyst 9200 Series Switches Umbrella Connector Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
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.
7PK - Errors
7PK - Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.