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CVE-2023-20198

Published: Oct 16, 2023Updated: Oct 28, 2025 Sources: CVE List NVD BDU csafCWE-420
10.0CRITICAL
NVD MITRE
EPSS Score
99.6%
Top 0.1%
CISA KEV
Active Exploitation
Since Oct 16, 2023
Exploits
1 Known
Remediation
Patch Available
Self-Check
Nuclei · OpenVAS

Description

Cisco 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.

In plain language

AI Act now

CVE-2023-20198 is a critical flaw in the Cisco IOS XE web interface that lets an attacker without a login create a new local username and password, which can then lead to a full system takeover—so RED, and you should act quickly if your device’s web UI is reachable from untrusted networks.

Executive summary

CVE-2023-20198 is an unauthenticated network vulnerability in the Cisco IOS XE Software web UI feature that enables attackers to create a local user/password, enabling follow-on actions like privilege escalation and implant deployment.

If affected, business impact
Device takeoverMalware/implant installationLoss of network availabilityUnauthorized access credentials

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-420NVD-CWE-Other

Affected Products

Cisco Systems Inc.
commercial·USaka Cisco, cisco systems
Cisco IOS XEOn-premFirmware
Networking Infrastructure / router-switch
Cisco IOS XE Software
Networking Infrastructure
rockwellautomation
commercial·USaka rockwell automation
allen-bradley stratix 5200 firmware
ICS / OT / IoT
allen-bradley stratix 5800 firmware
ICS / OT / IoT
and 1 more affected products View all →

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Oct 16, 2023
Remediation due:Oct 20, 2023

Required action: Verify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. For affected products (Cisco IOS XE Web UI exposed to the internet or to untrusted networks), follow vendor instructions to determine if a system may have been compromised and immediately report positive findings to CISA.

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available
Workaround Available
Is your org exposed to CVE-2023-20198?We'll check your whole external perimeter for exposure — free. Check my exposure

References

https://arstechnica.com/security/2023/10/actively-exploited-cisco-0-day-with-maximum-10-severity-gives-full-network-control/
arstechnica.com
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-webui-privesc-j22SaA4z
sec.cloudapps.cisco.com
https://www.darkreading.com/vulnerabilities-threats/critical-unpatched-cisco-zero-day-bug-active-exploit
darkreading.com
and 15 more references View all →
News mentions
2

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