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iOSOperating system · Cisco

CVE-2021-1391

MEDIUM · 6.7 CVSS v3.1 Published 2021-03-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

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 · unedited
A vulnerability in the dragonite debugger of Cisco IOS XE Software could allow an authenticated, local attacker to escalate from privilege level 15 to root privilege. The vulnerability is due to the presence of development testing and verification scripts that remained on the device. An attacker could exploit this vulnerability by bypassing the consent token mechanism with the residual scripts on the affected device. A successful exploit could allow the attacker to escalate from privilege level 15 to root privilege.

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 confidence

A vulnerability in the dragonite debugger of Cisco IOS XE Software allows an authenticated, local attacker with privilege level 15 to escalate to root privileges. The root cause is development testing and verification scripts that were inadvertently left on production devices, allowing the attacker to bypass the consent token security mechanism.

MitigationApply the Cisco IOS XE software update that removes the residual development scripts from the dragonite debugger. If immediate patching is not possible, restrict local access to trusted administrators and monitor for any unauthorized root-level access attempts.

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
iOSOperating system
Affected:= 12.2\(6\)i1= 15.0\(2\)se13a= 15.1\(3\)svr1= 15.1\(3\)svr2= 15.1\(3\)svr3= 15.1\(3\)svs= 15.1\(3\)svs1= 15.2\(4\)ea10= 15.2\(5\)e= 15.2\(5\)e1= 15.2\(5\)e2= 15.2\(5\)e2b
Ios XeOperating system
Affected:= 3.9.0e= 3.9.1e= 3.9.2be= 3.9.2e= 3.10.0ce= 3.10.0e= 3.10.1ae= 3.10.1e= 3.10.1se= 3.10.2e= 3.10.3e= 3.11.0e

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 checks

Work through these to decide whether this CVE applies to you.

  1. Determine the Cisco IOS XE version
    Run 'show version' or 'show version | include Version' to obtain the installed software version
    Affected if The version matches one of the affected ranges: 3.9.0e, 3.9.1e, 3.9.2be, 3.9.2e, 3.10.0ce, 3.10.0e, 3.10.1ae, 3.10.1e, 3.10.1se, 3.10.2e, 3.10.3e, or 3.11.0e
  2. Determine the Cisco IOS version
    Run 'show version' on IOS devices (not IOS XE) to obtain the installed software version
    Affected if The version matches one of the affected ranges: 12.2(6)i1, 15.0(2)se13a, 15.1(3)svr1, 15.1(3)svr2, 15.1(3)svr3, 15.1(3)svs, 15.1(3)svs1, 15.2(4)ea10, 15.2(5)e, 15.2(5)e1, 15.2(5)e2, or 15.2(5)e2b
  3. Verify if the dragonite debugger is accessible
    Attempt to access the dragonite debugger via the CLI, typically through debug commands or by checking if debug shell commands are available to the current user
    Affected if The dragonite debugger command interface is available and can be invoked on the device
  4. Confirm privilege level 15 access exists
    Check the current user privilege level using 'show privilege' or verify that an account with privilege level 15 exists on the system
    Affected if An authenticated user with privilege level 15 credentials can access the device locally

The device is affected if it runs a Cisco IOS or IOS XE version matching the affected list AND has the dragonite debugger accessible to an authenticated privilege level 15 user, allowing the development scripts to be exploited for privilege escalation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco IOS XE software update that removes the residual development scripts from the dragonite debugger. If immediate patching is not possible, restrict local access to trusted administrators and monitor for any unauthorized root-level access attempts.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,960
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-1391 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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