Nx OsOperating system · Cisco
CVE-2019-1809
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 patch on an affected device. The vulnerability is due to improper verification of digital signatures for patch images. An attacker could exploit this vulnerability by crafting an unsigned software patch to bypass signature checks and loading it on an affected device. A successful exploit could allow the attacker to boot a malicious software patch image.
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 confidenceA local privilege escalation vulnerability in Cisco NX-OS Image Signature Verification allows an authenticated administrator to bypass digital signature checks when installing software patches. An attacker can craft a malicious unsigned patch that bypasses signature validation, enabling boot of a compromised software image.
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
>= 7.3, < 8.1\(1a\)>= 8.2, < 8.3\(1\)>= 7.2, < 7.3\(3\)d1\(1\)>= 8.0, < 8.2\(3\)>= 3.1, < 3.2\(3k\)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.
-
Identify installed NX-OS versionRun 'show version' or access the system ROM monitor to retrieve the currently running NX-OS software versionAffected if The installed version falls within any of the following ranges: >= 7.3 and < 8.1(1a); >= 8.2 and < 8.3(1); >= 7.2 and < 7.3(3)d1(1); >= 8.0 and < 8.2(3); >= 3.1 and < 3.2(3k)
-
Verify image signature verification feature statusCheck the NX-OS configuration for image signature verification settings using 'show running-config | include signature' or similar configuration review commandsAffected if Image signature verification is configured and the NX-OS version is vulnerable as identified in step 1
-
Review recent patch installation logsExamine system logs, install logs, or audit records for any software patch installations that may have occurred recently using 'show install log' or review syslog exportsAffected if Any patch installations are present in the logs and the system is running a vulnerable NX-OS version
-
Audit administrator account activityReview authentication logs and administrator command history for any unusual or unauthorized patch installation commandsAffected if Evidence of patch installation commands exists and the NX-OS version is within the affected ranges
A system is likely affected if it runs any Cisco NX-OS version matching the affected ranges and has image signature verification enabled, as the vulnerability allows bypassing this security control.
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 data3.27.38.1
Apply the Cisco patch for this vulnerability; restrict administrator-level access and monitor for unauthorized patch installations until the vendor update is applied.
Fix this in Nx Os
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-1809 — 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-2019-1809 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