Ios XeOperating system · Cisco

CVE-2017-12229

CRITICAL · 9.8 CVSS v3.0 Published 2017-09-29

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

100/100

Remediation priority · Urgent

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

A vulnerability in the REST API of the web-based user interface (web UI) of Cisco IOS XE 3.1 through 16.5 could allow an unauthenticated, remote attacker to bypass authentication to the REST API of the web UI of the affected software. The vulnerability is due to insufficient input validation for the REST API of the affected software. An attacker could exploit this vulnerability by sending a malicious API request to an affected device. A successful exploit could allow the attacker to bypass authentication and gain access to the web UI of the affected software. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, if the HTTP Server feature is enabled for the device. The newly redesigned, web-based administration UI was introduced in the Denali 16.2 Release of Cisco IOS XE Software. This vulnerability does not affect the web-based administration UI in earlier releases of Cisco IOS XE Software. Cisco Bug IDs: CSCuz46036.

Technical summary

dbcve analysis · high confidence

A critical authentication bypass vulnerability exists in the REST API of Cisco IOS XE web UI (versions 3.1 through 16.5). The vulnerability stems from insufficient input validation in the REST API, allowing unauthenticated remote attackers to send malicious API requests that bypass authentication entirely and gain access to the web interface. This only affects devices with the HTTP Server feature enabled and applies specifically to the redesigned web-based admin UI introduced in Denali 16.2.

MitigationDisable the HTTP Server feature on affected Cisco IOS XE devices if not required, and upgrade to a Cisco IOS XE version with the security patch for CSCuz46036.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

Ios XeOperating system

Affected:= 3.1.3as= 3.2.0ja= 3.2.1xo= 3.4.7asg= 3.6.5be= 3.8.0ex= 3.18.3vs= 16.1.1= 16.1.2= 16.1.3= 16.1.3a= 16.1.4

CVSS breakdown

From the vector

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

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected?

dbcve checks

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

Identify the device OS and version

Run 'show version' or 'show running-config | include ios' to identify the operating system and installed version

Affected if The device runs Cisco IOS XE and the version matches 3.1.3as, 3.2.0ja, 3.2.1xo, 3.4.7asg, 3.6.5be, 3.8.0ex, 3.18.3vs, 16.1.1, 16.1.2, 16.1.3, 16.1.3a, or 16.1.4 (or falls within 3.1 through 16.5 range)
Verify HTTP Server feature is enabled

Run 'show running-config | include ip http server' or 'show webui status' to check if the HTTP Server feature is active

Affected if HTTP Server is enabled (the vulnerability only affects devices with this feature)
Confirm web UI REST API endpoint accessibility

Attempt to access the REST API endpoint (typically https://<device-ip>/api) without credentials to see if authentication is bypassed

Affected if Unauthenticated API requests return valid responses or bypass authentication prompts
Check for Denali 16.2+ web UI

Review 'show webui config' or access the web interface to identify if it is the redesigned admin UI introduced in Denali 16.2

Affected if The device uses the redesigned web-based admin UI from Denali 16.2 or later

The device is affected if it runs Cisco IOS XE versions 3.1 through 16.5, has the HTTP Server feature enabled, and uses the Denali 16.2+ redesigned web UI.

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

Remediation

dbcve · scoped

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Disable the HTTP Server feature on affected Cisco IOS XE devices if not required, and upgrade to a Cisco IOS XE version with the security patch for CSCuz46036.

Recommended fix Moderate confidence

Upgrade to a stable IOS XE release newer than 16.5 (e.g., 16.6.x or later stable release) - contact Cisco TAC for the exact recommended fixed release for your hardware platform

1. Identify the currently running Cisco IOS XE version using 'show version' command
2. Confirm the HTTP Server feature is enabled using 'show running-config | include ip http server'
3. If HTTP Server is not required for operations, disable it using 'no ip http server' in global configuration mode as a temporary mitigation
4. Schedule a maintenance window for the IOS XE upgrade
5. Download the fixed IOS XE release from Cisco using your valid service contract at downloads.cisco.com
6. Backup the current device configuration using 'copy running-config startup-config' or export via TFTP/FTP
7. Upgrade the IOS XE image using the appropriate method (USB, ROMmon, or IOS XE installer)
8. After upgrade, verify the HTTP Server status and confirm the new version is running with 'show version'

Caveat Review Cisco IOS XE release notes for potential configuration or feature changes between your current version and the target upgrade version; some legacy HTTP management interfaces may behave differently in newer releases

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
Testing6.0 h
Review / QA2.0 h

20.0 hours of engineering $3,500

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Scan for this in your stack

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References

Primary sources

tools.cisco.comVendor Advisory
www.securityfocus.comThird Party AdvisoryVDB Entry
www.securitytracker.comThird Party AdvisoryVDB Entry
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-12229 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2017-12229?

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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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

At a glance

A fix existsA vendor remedy is published

Severity 9.8 Critical

Exploit likelihood EPSS, next 30 days 5.1%

Affects: Ios Xe

Remediation

A high-priority fix

Fix this in Ios Xe 20 hrs · Moderate

Typical engagement from $3,500

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2017-12229 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

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

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References