Security readout for executives and security teams
Plain-English summary
This flaw can make specific Cisco Catalyst 4000 switches stop handling important control and management functions. An unauthenticated remote attacker could send crafted TCP traffic to the switch itself and exhaust buffer resources, causing a denial of service. The cited sources do not show active exploitation.
Executive priority
Treat this as high priority for legacy network infrastructure, especially where switch management addresses are broadly reachable. The business risk is loss of network control and management availability rather than data theft.
Technical view
CVE-2019-12652 affects Cisco IOS Software on Cisco Catalyst 4000 Series Switches, specifically listed as Cisco IOS 15.0(1)XO1. Improper resource allocation in ingress TCP packet processing can exhaust buffers when TCP traffic is directed at the device. Transit traffic through the switch is not enough to trigger it.
Likely exposure
Exposure is most likely where affected Catalyst 4000 devices are reachable over TCP on management or control-plane addresses. Devices only forwarding transit traffic are not exposed through that path, according to the CVE description.
Exploitation context
The vulnerability is remote, unauthenticated, and low complexity with high availability impact. The source bundle says exploitation requires crafted TCP streams destined to an affected device. It does not cite CISA KEV listing, observed exploitation, public exploit availability, or a confirmed patch version.
Researcher notes
The key boundary is destination traffic: the flaw is triggered by TCP traffic sent to the switch itself, not traffic transiting the switch. The provided evidence is limited to CVE data and Cisco’s advisory reference, so fix details should be confirmed directly with Cisco.
Mitigation direction
- Check Cisco’s advisory for fixed software or vendor-recommended remediation.
- Inventory Catalyst 4000 switches and verify IOS versions against the advisory.
- Limit TCP access to switch device addresses to trusted management networks where feasible.
- Prioritize exposed management-plane interfaces over devices reachable only from controlled networks.
- Monitor affected switches for management or control-plane DoS symptoms.
Validation and detection
- Confirm whether any Catalyst 4000 switches run Cisco IOS 15.0(1)XO1.
- Map which networks can send TCP traffic to switch device addresses.
- Review logs and telemetry for control-plane or management-plane degradation.
- Verify remediation status against Cisco’s advisory, not only generic CVE data.
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-399: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-12652 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
- 20190925 Cisco Catalyst 4000 Series Switches TCP 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.
Resource Management Errors
Resource Management Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.