Sg250x 24 FirmwareOperating system · Cisco
CVE-2020-3121
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 · uneditedA vulnerability in the web-based management interface of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface. The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected device. An attacker could exploit this vulnerability by persuading a user of the interface to click a malicious link and access a specific page. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
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 confidenceCross-site scripting (XSS) vulnerability in the web-based management interface of Cisco Small Business Smart and Managed Switches. The flaw stems from insufficient validation of user-supplied input, allowing an unauthenticated remote attacker to inject malicious script through a crafted link that tricks users into accessing a specific page.
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
<= 2.5.0.90
Sg250x 24p FirmwareOperating system
<= 2.5.0.90
Sg250x 48 FirmwareOperating system
<= 2.5.0.90
Sg250x 48p FirmwareOperating system
<= 2.5.0.90
Sg250 08 FirmwareOperating system
<= 2.5.0.90
Sg250 08hp FirmwareOperating system
<= 2.5.0.90
Sg250 10p FirmwareOperating system
<= 2.5.0.90
Sg250 18 FirmwareOperating system
<= 2.5.0.90CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Identify the switch modelAccess the switch CLI or web interface and retrieve the hardware model identifier (e.g., Sg250x 24, Sg250 08, etc.) or check the device labelAffected if The model is one of: Sg250x 24, Sg250x 24p, Sg250x 48, Sg250x 48p, Sg250 08, Sg250 08hp, Sg250 10p, or Sg250 18
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Check the installed firmware versionLog into the switch web interface and navigate to the Administration > Firmware Upgrade page, or use the CLI command 'show version' to retrieve the firmware versionAffected if The firmware version is 2.5.0.90 or lower (any version up to and including 2.5.0.90)
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Verify if web-based management interface is enabledIn the web interface, go to Administration > Management Interface > HTTP/HTTPS Settings, or use the CLI command 'show http server' to check if the HTTP or HTTPS web server is enabledAffected if HTTP or HTTPS web management is enabled (the vulnerability exists in the web interface regardless of whether HTTP or HTTPS is used)
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Assess network exposure of the web interfaceCheck if the switch management IP is accessible from untrusted networks by reviewing your network segmentation and firewall rules, or attempt to reach the web interface from an external IPAffected if The management interface is reachable from untrusted networks or the internet without proper access controls
You are affected if you have a Cisco Sg250x or Sg250 series switch running firmware version 2.5.0.90 or lower with the web-based management interface enabled and exposed to potential attackers.
Generated from the published advisory. Verify against your own configuration.
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 dataApply Cisco's available firmware updates for affected switch models; users should avoid clicking untrusted links to the management interface.
Fix this in Sg250x 24 Firmware
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3121 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3121 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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