Ios XeOperating system · Cisco
CVE-2023-20198
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 · uneditedCisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software. We are updating the list of fixed releases and adding the Software Checker. Our investigation has determined that the actors exploited two previously unknown issues. The attacker first exploited CVE-2023-20198 to gain initial access and issued a privilege 15 command to create a local user and password combination. This allowed the user to log in with normal user access. The attacker then exploited another component of the web UI feature, leveraging the new local user to elevate privilege to root and write the implant to the file system. Cisco has assigned CVE-2023-20273 to this issue. CVE-2023-20198 has been assigned a CVSS Score of 10.0. CVE-2023-20273 has been assigned a CVSS Score of 7.2. Both of these CVEs are being tracked by CSCwh87343.
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 confidenceCVE-2023-20198 is a critical vulnerability in the web UI feature of Cisco IOS XE Software that allows unauthenticated attackers to execute privilege 15 commands, enabling creation of a local administrative user. This vulnerability is actively exploited in the wild as part of a two-stage attack chain (paired with CVE-2023-20273 for privilege escalation to root).
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
>= 16.12, < 16.12.10a>= 17.3, < 17.3.8a>= 17.6, < 17.6.6a>= 17.9, < 17.9.4a< 17.12.02< 17.12.02CVSS 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
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 checksWork through these to decide whether this CVE applies to you.
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Confirm web UI is enabledRun 'show ip http server status' or 'show ip http server secure status' to see if the HTTP or HTTPS server is activeAffected if HTTP or HTTPS server status shows as enabled - the vulnerability only affects systems with the web UI feature running
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Identify the IOS XE versionRun 'show version' and locate the IOS XE software version string (typically in the format 17.x.x or 16.x.x)Affected if Version falls within any of these ranges: 16.12.x before 16.12.10a, 17.3.x before 17.3.8a, 17.6.x before 17.6.6a, 17.9.x before 17.9.4a, or the device is a Rockwell Stratix 5200/5800 with firmware before 17.12.02
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Audit local user accountsRun 'show running-config | include username' to list all configured local users, then run 'show privilege' to check your current privilege levelAffected if Any unexpected username exists with privilege level 15, or you discover you are not the only admin who should have level 15 access
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Check for unauthorized configuration changesRun 'show archive config differences' (if archive logging is enabled) or review configuration logs for unexpected 'username' commands added to the configurationAffected if Configuration changes include new username entries with privilege 15 that were not intentionally added
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Examine system logs for exploitation indicatorsCheck system logs for failed authentication attempts followed by successful privileged user creation, or search for the specific attack pattern: unauthenticated requests to '/webui' endpointsAffected if Logs show creation of new privilege 15 users without corresponding legitimate admin sessions, or unusual web UI access patterns from unknown sources
A system is likely affected if it runs a vulnerable IOS XE version with the web UI enabled and shows evidence of unauthorized privilege 15 users or configuration changes.
Generated from the published advisory. Verify against your own configuration.
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 · scoped16.12.10a17.3.8a17.6.6a
Apply Cisco's fixed IOS XE releases immediately, disable the web UI feature if not required, and audit existing devices for unauthorized local users or file system implants.
Upgrade to IOS XE 16.12.10a, 17.3.8a, 17.6.6a, or 17.9.4a (or later respective releases)
- Identify the current IOS XE version by running 'show version' on the device
- Confirm the version falls within one of the affected ranges: 16.12.x before 16.12.10a, 17.3.x before 17.3.8a, 17.6.x before 17.6.6a, or 17.9.x before 17.9.4a
- Schedule a maintenance window as this vulnerability is being actively exploited in the wild
- Obtain the appropriate fixed release from Cisco's software download center (16.12.10a or later, 17.3.8a or later, 17.6.6a or later, or 17.9.4a or later)
- Upload the new image to the device bootflash using TFTP, FTP, or SCP
- Configure the device to boot from the new image using 'boot system bootflash:<filename>'
- Reload the device using 'reload' command
- After reboot, verify the new version is running with 'show version' and confirm the local user account created by the attacker has been removed
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ios Xe
Exploited in the wild — priority engagement
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,352.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-20198 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-20198 in production — separate from our analysis above.
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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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