Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker crash and reload affected Cisco Small Business managed switches through the web interface. The business impact is availability: network segments relying on these switches could briefly lose connectivity or suffer repeated disruption if exposed.
Executive priority
Treat as a high-priority network availability risk, especially for internet-reachable or broadly reachable management interfaces. Prioritize identifying exposed switches and following Cisco guidance before disruption affects business operations.
Technical view
CVE-2019-1891 is an improper input validation issue in the HTTP web interface of Cisco Small Business 200, 300, and 500 Series Managed Switches. The CVSS 3.0 score is 7.5: network reachable, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely where affected Cisco Small Business switches have their management web interface reachable from untrusted networks. The source bundle does not specify affected firmware versions beyond the product families.
Exploitation context
The source states unauthenticated remote exploitation is possible by a malicious web-interface request causing unexpected device reload. No CISA KEV listing or provided source supports active exploitation in the wild.
Researcher notes
The available evidence identifies CWE-20 improper validation in the web interface and a DoS outcome only. It does not provide exploit details, affected version ranges, named fixes, or observed exploitation.
Mitigation direction
- Review Cisco advisory cisco-sa-20190703-sbss-dos for affected releases and vendor fixes.
- Apply Cisco-recommended fixed software or workarounds where applicable.
- Restrict switch web management access to trusted administrative networks.
- Monitor affected switches for unexpected reloads and repeated availability loss.
Validation and detection
- Inventory Cisco Small Business 200, 300, and 500 Series Managed Switches.
- Check whether each device exposes the web interface beyond trusted administrators.
- Compare installed software versions against Cisco’s advisory guidance.
- Review logs and uptime for unexplained reloads or repeated management-plane crashes.
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-20: 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-2019-1891 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
- 7.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/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:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.5HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190703 Cisco Small Business Series Switches HTTP 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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.