dbcve.org
Sg250x 24 FirmwareOperating system · Cisco

CVE-2020-3363

HIGH · 8.6 CVSS v3.1 Published 2020-08-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
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
A vulnerability in the IPv6 packet processing engine of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of incoming IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet through an affected device. A successful exploit could allow the attacker to cause an unexpected reboot of the switch, leading to a DoS condition. This vulnerability is specific to IPv6 traffic. IPv4 traffic is not affected.

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 · high confidence

A vulnerability in the IPv6 packet processing engine of Cisco Small Business Smart and Managed Switches allows an unauthenticated remote attacker to cause denial of service by sending a crafted IPv6 packet through the device, triggering an unexpected reboot. The vulnerability stems from insufficient validation of incoming IPv6 traffic, and affects only IPv6 traffic flows.

MitigationApply the vendor-supplied firmware patch for this vulnerability. Until patched, consider filtering or rate-limiting IPv6 traffic on affected devices as a temporary workaround.

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
Sg250x 24 FirmwareOperating system
Affected:all versions
Sg250x 24p FirmwareOperating system
Affected:all versions
Sg250x 48 FirmwareOperating system
Affected:all versions
Sg250x 48p FirmwareOperating system
Affected:all versions
Sg250 08 FirmwareOperating system
Affected:all versions
Sg250 08hp FirmwareOperating system
Affected:all versions
Sg250 10p FirmwareOperating system
Affected:all versions
Sg250 18 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
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/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 the switch model
    Log into the device web interface or CLI and retrieve the hardware model number. In the web interface, this is typically shown on the Dashboard or in the System Summary. In CLI, use 'show version' or 'show system' commands.
    Affected if The model is one of: Sg250x 24, Sg250x 24p, Sg250x 48, Sg250x 48p, Sg250 08, Sg250 08hp, Sg250 10p, or Sg250 18.
  2. Confirm IPv6 is enabled on the device
    In the web interface, navigate to IPv6 Configuration or IP Configuration settings and verify if IPv6 is turned ON. In CLI, use 'show ipv6 interface' or check the IPv6 settings under IP Configuration.
    Affected if IPv6 is enabled on the switch. The vulnerability only affects IPv6 traffic flows.
  3. Check if IPv6 traffic can reach the device
    Verify the network configuration to determine if the switch has an IPv6 address assigned and is accessible over IPv6. Use 'show ipv6 interface' in CLI to list active IPv6 addresses on each VLAN interface.
    Affected if The switch has an IPv6 address configured and is reachable via IPv6 on any VLAN interface.
  4. Verify firmware version for record
    In the web interface, go to Administration > Firmware Upgrade or System > Management to view the current firmware version. In CLI, use 'show version' to display the firmware build.
    Affected if All firmware versions of the listed models are vulnerable. This step confirms the device falls within the affected product list.

If the device is any of the Sg250 series models (250x 24/24p/48/48p or 250 08/08hp/10p/18) with IPv6 enabled and an IPv6 address configured, the environment is affected by this CVE.

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 the vendor-supplied firmware patch for this vulnerability. Until patched, consider filtering or rate-limiting IPv6 traffic on affected devices as a temporary workaround.

Fix this in Sg250x 24 Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2020-3363 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