CVE-2021-28494
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 · uneditedIn Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, authentication is bypassed by unprivileged users who are accessing the Web UI. This issue affects: Arista Metamako Operating System MOS-0.34.0 and prior releases
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 confidenceAuthentication bypass vulnerability in Arista MOS (Metamako Operating System) Web UI allows unprivileged users to gain unauthorized access under certain conditions. This affects the 7130 product line running MOS-0.34.0 and prior versions, potentially enabling attackers to bypass authentication controls in the web interface.
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<= 0.34.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
-
Identify Arista 7130 device running MOSCheck the device model and confirm it is part of the Arista 7130 product line running Metamako Operating System. This may be visible in the device inventory, network documentation, or by running 'show version' or 'show system' commands on the device CLI.Affected if The device is an Arista 7130 series running MOS (Metamako Operating System)
-
Determine MOS versionRun the command to display the MOS version, such as 'show version' or 'show system information' in the Arista CLI. Look for the MOS version number in the output.Affected if The displayed MOS version is 0.34.0 or any earlier version (e.g., 0.33.x, 0.32.x, etc.)
-
Verify Web UI is enabledCheck the device configuration for the Web UI service. This may involve running 'show running-config' or similar commands to look for http, https, or webui related service configurations.Affected if The Web UI service (HTTP or HTTPS) is enabled and listening on the device
-
Check Web UI exposureReview the network configuration to determine if the Web UI is accessible from external interfaces or untrusted networks. Look for interface bindings, ACLs, or firewall rules applied to the Web UI service.Affected if The Web UI is bound to externally accessible interfaces without proper network restrictions
A user is affected if they are running MOS version 0.34.0 or earlier on an Arista 7130 device with the Web UI enabled and exposed.
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 vendor-supplied patches for MOS; until then, restrict network access to the Web UI using firewall rules or ACLs to limit exposure to untrusted networks.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-28494 — 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-2021-28494 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No spam, self-promotion, credentials, or personal data