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iOSOperating system · Cisco

CVE-2021-1392

HIGH · 7.8 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 →
80/100
Remediation priority · High
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 CLI command permissions of Cisco IOS and Cisco IOS XE Software could allow an authenticated, local attacker to retrieve the password for Common Industrial Protocol (CIP) and then remotely configure the device as an administrative user. This vulnerability exists because incorrect permissions are associated with the show cip security CLI command. An attacker could exploit this vulnerability by issuing the command to retrieve the password for CIP on an affected device. A successful exploit could allow the attacker to reconfigure the 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 confidence

A vulnerability in Cisco IOS and IOS XE CLI command permissions allows authenticated local attackers to retrieve the Common Industrial Protocol (CIP) password via the improperly secured 'show cip security' command. The incorrect permissions on this command enable any local user to obtain credentials that can then be used to reconfigure the device with administrative privileges remotely.

MitigationApply Cisco IOS/IOS XE software updates that correct the permissions on the 'show cip security' command; until patched, strictly limit physical and console access to trusted administrators only.

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:= 15.0\(1\)ey= 15.0\(1\)ey1= 15.0\(1\)ey2= 15.1\(3\)svs= 15.1\(3\)svt1= 15.2\(1\)ey= 15.2\(2\)e= 15.2\(2\)e1= 15.2\(2\)e2= 15.2\(2\)e3= 15.2\(2\)e4= 15.2\(2\)e5
Ios XeOperating system
Affected:= 3.3.0xo= 3.3.1xo= 3.3.2xo= 3.6.5be= 3.7.4e= 3.7.5e= 16.9.1= 16.9.1d= 16.10.1= 16.10.1e= 16.11.1= 16.11.1a

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/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 checks

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

  1. Identify installed Cisco IOS or IOS XE version
    Execute the 'show version' command on the device CLI to retrieve the exact software version
    Affected if The displayed version matches any of the affected versions listed in the CVE advisory
  2. Verify CIP protocol is configured on the device
    Run 'show running-config | include cip' or check for CIP-related configuration in the device configuration
    Affected if CIP protocol is enabled or configured on the device, making the vulnerable command relevant
  3. Test 'show cip security' command accessibility
    Attempt to execute 'show cip security' from a non-privileged or low-privilege user account (e.g., a regular user account without admin rights)
    Affected if The command executes successfully and displays CIP security information including passwords to a non-privileged user, confirming the permission vulnerability
  4. Check for CIP password exposure
    Execute 'show cip security' and examine the output for plaintext passwords or credential data
    Affected if The command output contains CIP authentication credentials that should not be accessible to non-administrative users

You are affected if your device runs an affected Cisco IOS or IOS XE version, has CIP protocol configured, and allows non-privileged users to execute 'show cip security' and view sensitive credentials.

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 Cisco IOS/IOS XE software updates that correct the permissions on the 'show cip security' command; until patched, strictly limit physical and console access to trusted administrators only.

Fix this in iOS Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2021-1392 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
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  • No spam, self-promotion, credentials, or personal data