Ios XeOperating system · Cisco
CVE-2021-1281
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 CLI management in Cisco IOS XE SD-WAN Software could allow an authenticated, local attacker to access the underlying operating system as the root user. This vulnerability is due to the way the software handles concurrent CLI sessions. An attacker could exploit this vulnerability by authenticating to the device as an administrative user and executing a sequence of commands. A successful exploit could allow the attacker to obtain access to the underlying operating system as the root user.
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 IOS XE SD-WAN Software's CLI management allows an authenticated administrative user to gain root access to the underlying operating system by exploiting improper handling of concurrent CLI sessions through a specific sequence of commands.
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
Ios XeOperating system
= 16.9.1= 16.9.2= 16.9.3= 16.9.4= 16.10.1= 16.10.1a= 16.10.1b= 16.10.1c= 16.10.1d= 16.10.1e= 16.10.1f= 16.10.1gCVSS 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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Confirm Cisco IOS XE SD-WAN is in useRun 'show sdwan version' or 'show version' and look for IOS XE with SD-WAN capability in the software descriptionAffected if The device runs Cisco IOS XE with SD-WAN functionality enabled
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Identify the installed IOS XE versionRun 'show version' and locate the software version number in the output (typically displayed as 16.9.x or 16.10.x)Affected if The version matches any of: 16.9.1, 16.9.2, 16.9.3, 16.9.4, 16.10.1, 16.10.1a, 16.10.1b, 16.10.1c, 16.10.1d, 16.10.1e, 16.10.1f, or 16.10.1g
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Verify CLI management interface is accessibleAttempt to access the CLI via console, SSH, or telnet and confirm administrative access is available using 'show priv' to display current privilege levelAffected if An authenticated administrative CLI session can be established (privilege level 15 typically indicates full administrative access)
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Check for concurrent CLI session configurationRun 'show users' or 'show line' to view active CLI sessions on the deviceAffected if Multiple concurrent administrative CLI sessions are active or have been recorded
A device is affected if it runs any of the listed Cisco IOS XE versions (16.9.1 through 16.10.1g) with SD-WAN functionality and allows authenticated administrative CLI access.
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 the vendor-provided patch for this vulnerability. Restrict administrative CLI access to trusted personnel and monitor for unauthorized privilege escalation attempts.
Fix this in Ios Xe
Scoped from the published advisory
- Consultation6.0 h
- Implementation4.0 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 $4,608.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1281 — 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-2021-1281 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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