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Ios XeOperating system · Cisco

CVE-2023-20066

MEDIUM · 6.5 CVSS v3.1 Published 2023-03-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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 web UI of Cisco IOS XE Software could allow an authenticated, remote attacker to perform a directory traversal and access resources that are outside the filesystem mountpoint of the web UI. This vulnerability is due to an insufficient security configuration. An attacker could exploit this vulnerability by sending a crafted request to the web UI. A successful exploit could allow the attacker to gain read access to files that are outside the filesystem mountpoint of the web UI. Note: These files are located on a restricted filesystem that is maintained for the web UI. There is no ability to write to any files on this filesystem.

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 directory traversal vulnerability exists in the web UI of Cisco IOS XE Software due to insufficient security configuration. An authenticated attacker can send crafted requests containing path traversal sequences (e.g., ../) to access files outside the web UI's designated filesystem mountpoint, gaining read access to restricted system files.

MitigationApply the Cisco security update/patch for CVE-2023-20066 to affected IOS XE devices. If patching is immediately unavailable, restrict web UI access to trusted networks or disable the web UI if not required, and monitor for suspicious path traversal requests.

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:= 16.12.3= 17.3.2= 17.6.2

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
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 installed Cisco IOS XE version
    Execute 'show version' on the device CLI and locate the IOS XE version string (typically in the format 16.x.x, 17.x.x, etc.)
    Affected if The version matches exactly 16.12.3, 17.3.2, or 17.6.2
  2. Verify if the web UI HTTP server is enabled
    Run 'show running-config | include ip http server|ip http secure server' to check if the HTTP or HTTPS server is configured
    Affected if Either 'ip http server' or 'ip http secure-server' appears in the running configuration, indicating the web UI is active
  3. Confirm web UI authentication is in use
    Run 'show running-config | include ip http' to check authentication settings and verify whether the HTTP server requires authentication
    Affected if The HTTP server is enabled and authentication is configured (default behavior), making the vulnerability reachable with valid credentials
  4. Review system logs for path traversal attempts
    Execute 'show logging' or check syslog/server buffers for requests containing '../', '..\', or unusual file access patterns targeting system files outside the web UI mountpoint
    Affected if Logs contain suspicious requests with directory traversal sequences targeting sensitive system files such as /etc/passwd, config memory, or nvram

You are affected if your device runs IOS XE version 16.12.3, 17.3.2, or 17.6.2 AND has the web UI (HTTP/HTTPS server) enabled and accessible with valid 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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco security update/patch for CVE-2023-20066 to affected IOS XE devices. If patching is immediately unavailable, restrict web UI access to trusted networks or disable the web UI if not required, and monitor for suspicious path traversal requests.

Recommended fix Moderate confidence

Upgrade to the latest stable Cisco IOS XE release in your current train (16.12.x, 17.3.x, or 17.6.x - specifically a release later than 17.6.2 recommended)

  1. 1. Identify the current Cisco IOS XE version running on the affected device using 'show version' command
  2. 2. Back up the current device configuration to a secure location
  3. 3. Download the fixed IOS XE software release from Cisco (later than the affected versions 16.12.3, 17.3.2, or 17.6.2)
  4. 4. Upload the new IOS XE image to the device's bootflash or storage
  5. 5. Configure the device to boot from the new image using 'boot system' command
  6. 6. Reload the device to apply the new software version
  7. 7. After reboot, verify the device is running the fixed version with 'show version'
  8. 8. Confirm the web UI is functional and the vulnerability is remediated
Caveat Standard IOS XE upgrade risks apply - ensure configuration compatibility and plan for potential downtime

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2023-20066 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