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Business 250 16p 2g FirmwareOperating system · Cisco

CVE-2023-20158

CRITICAL · 9.8 CVSS v3.1 Published 2023-05-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Multiple vulnerabilities in the web-based user interface of certain Cisco Small Business Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges on an affected device. These vulnerabilities are due to improper validation of requests that are sent to the web interface. For more information about these vulnerabilities, see the Details section of this advisory.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Multiple critical vulnerabilities in the web UI of Cisco Small Business Series Switches allow unauthenticated remote attackers to cause denial of service or execute arbitrary code with root privileges due to improper validation of HTTP requests.

MitigationApply Cisco-provided patches/updates for affected Small Business Series Switch firmware immediately; if patches unavailable, disable web-based management interface or restrict access via ACLs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Business 250 16p 2g FirmwareOperating system
Affected:all versions
Business 250 16t 2g FirmwareOperating system
Affected:all versions
Business 250 24fp 4g FirmwareOperating system
Affected:all versions
Business 250 24fp 4x FirmwareOperating system
Affected:all versions
Business 250 24p 4g FirmwareOperating system
Affected:all versions
Business 250 24p 4x FirmwareOperating system
Affected:all versions
Business 250 24pp 4g FirmwareOperating system
Affected:all versions
Business 250 24t 4g FirmwareOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify your switch model
    Log into the switch CLI and run 'show version' or check the physical device label to confirm the exact model number (e.g., CBS250-16P-2G, CBS250-24P-4X)
    Affected if The model is one of: CBS250-16P-2G, CBS250-16T-2G, CBS250-24FP-4G, CBS250-24FP-4X, CBS250-24P-4G, CBS250-24P-4X, CBS250-24PP-4G, or CBS250-24T-4G
  2. Verify the web UI is enabled
    Log into the switch CLI and run 'show running-config | include http' or access the web UI login page via HTTPS on port 443
    Affected if The HTTP or HTTPS web management interface is enabled (output shows http server enable or similar, or the web login page responds)
  3. Confirm web UI network exposure
    Check the management VLAN configuration with 'show vlan' and review interface settings to determine if the web UI is reachable from untrusted networks, or attempt to access the web UI from an external IP
    Affected if The web UI is accessible from outside the trusted management network (not restricted by ACLs, management VLAN isolation, or VPN)
  4. Check for unauthorized access indicators
    Review switch logs with 'show logging' or check for unexpected user accounts, new CGI scripts, or modified configuration files in the web UI filesystem
    Affected if Logs show unknown source IPs accessing the web UI, or unexpected configuration changes or new administrative accounts exist

You are affected if your switch is one of the eight Cisco Business 250 models and the web-based management interface is enabled and accessible from your network.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Cisco-provided patches/updates for affected Small Business Series Switch firmware immediately; if patches unavailable, disable web-based management interface or restrict access via ACLs.

Fix this in Business 250 16p 2g Firmware Scoped from the published advisory
  • Consultation5.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,370
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-20158 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data