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Ios XeOperating system · Cisco

CVE-2021-1441

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 hardware initialization routines of Cisco IOS XE Software for Cisco 1100 Series Industrial Integrated Services Routers and Cisco ESR6300 Embedded Series Routers could allow an authenticated, local attacker to execute unsigned code at system boot time. This vulnerability is due to incorrect validations of parameters passed to a diagnostic script that is executed when the device boots up. An attacker could exploit this vulnerability by tampering with an executable file stored on a device. A successful exploit could allow the attacker to execute unsigned code at boot time and bypass the software image verification check part of the secure boot process of an affected device. To exploit this vulnerability, the attacker would need administrative level credentials (level 15) on 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

This vulnerability in Cisco IOS XE Software allows an authenticated attacker with administrative (level 15) credentials to execute unsigned code during system boot by tampering with an executable file stored on the device. The root cause is insufficient validation of parameters passed to a diagnostic script that runs during boot, which enables bypass of the secure boot image verification process.

MitigationApply the Cisco patch/更新 for this vulnerability to the affected IOS XE software versions on the Cisco 1100 Series ISR and ESR6300 routers. Restrict administrative access and monitor for unauthorized physical access to prevent tampering of stored executable files.

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
Affected:= 3.15.1xbs= 3.15.2xbs= 16.9.1= 16.9.1c= 16.10.1= 16.10.1e= 16.11.1= 16.11.1c= 16.11.1s= 16.12.1= 16.12.1c= 16.12.1s

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. Identify the device is running Cisco IOS XE
    Run 'show version' and look for 'IOS XE' in the output, or check the boot prompt for 'IOS-XE'
    Affected if The device is not running Cisco IOS XE Software, then this CVE does not apply
  2. Determine the installed IOS XE version
    Run 'show version' and locate the version string (e.g., 'Version 16.9.1') in the output
    Affected if The installed version matches one of these: 3.15.1xbs, 3.15.2xbs, 16.9.1, 16.9.1c, 16.10.1, 16.10.1e, 16.11.1, 16.11.1c, 16.11.1s, 16.12.1, 16.12.1c, 16.12.1s
  3. Check if administrative (level 15) access is configured
    Run 'show running-config | include username' or 'show privilege' to see privilege level settings; verify whether level 15 accounts exist
    Affected if Unrestricted administrative accounts exist on the device, the exploitation path is available
  4. Verify the integrity of boot-related executable files
    Run 'show file verify' or 'dir flash:' to list files; compare file hashes against known-good values if available
    Affected if Any diagnostic or boot script files have been modified or tampered with on the device
  5. Check secure boot status if available
    Run 'show secure-boot' or look for secure boot configuration in 'show version' output
    Affected if Secure boot is disabled or not properly enforced on the device

A device is affected if it runs Cisco IOS XE versions 3.15.1xbs, 3.15.2xbs, 16.9.1, 16.9.1c, 16.10.1, 16.10.1e, 16.11.1, 16.11.1c, 16.11.1s, 16.12.1, 16.12.1c, or 16.12.1s and allows authenticated administrative access with potential for tamperable boot files.

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 patch/更新 for this vulnerability to the affected IOS XE software versions on the Cisco 1100 Series ISR and ESR6300 routers. Restrict administrative access and monitor for unauthorized physical access to prevent tampering of stored executable files.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2021-1441 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