Nx OsOperating system · Cisco
CVE-2019-1812
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 Image Signature Verification feature of Cisco NX-OS Software could allow an authenticated, local attacker with administrator-level credentials to install a malicious software image on an affected device. The vulnerability exists because software digital signatures are not properly verified during CLI command execution. An attacker could exploit this vulnerability to install an unsigned software image on an affected device.
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 confidenceThe Image Signature Verification feature in Cisco NX-OS fails to properly validate digital signatures during software image installation via CLI. An authenticated attacker with administrator credentials can bypass this check to install a malicious unsigned software image on the affected device.
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
Nx OsOperating system
>= 6.0\(2\), < 7.0\(3\)i7\(5\)>= 9.2, < 9.2\(2\)>= 7.0\(3\), < 7.0\(3\)f3\(5\)< 7.0\(3\)i7\(5\)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
- Local
- Complexity
- Low
- Privileges
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/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.
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Check installed NX-OS versionRun 'show version' command on the device CLI to display the current software versionAffected if The displayed version falls within any of these ranges: >= 6.0(2) and < 7.0(3)i7(5); >= 9.2 and < 9.2(2); >= 7.0(3) and < 7.0(3)f3(5); or < 7.0(3)i7(5)
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Verify Image Signature Verification feature statusRun 'show image signature verification' or 'show running-config | include signature' to check if signature verification is configured and enabledAffected if Signature verification is disabled or shows a configuration that can be bypassed, or if the command output indicates the feature is not enforcing signature checks during install
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Review recent software image installation logsRun 'show install logs' or 'show logging log' with timeframe filters to examine recent image installation events on the deviceAffected if Unsigned images were recently installed, or installation logs show signature verification was skipped or bypassed
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Check for unauthorized administrator account changesRun 'show user account' or 'show running-config | include user' to list administrator accounts and compare against known legitimate accountsAffected if New or unexpected administrator accounts exist that were not authorized by your organization
You are affected if your NX-OS version matches the vulnerable ranges AND Image Signature Verification is enabled but was bypassed, or if unsigned images were installed without detection.
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 data7.09.2
Apply the Cisco-provided patch or upgrade to a fixed NX-OS version. Restrict administrator-level access and monitor for unauthorized image installations.
Fix this in Nx Os
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 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 $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-1812 — 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-2019-1812 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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- 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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