VulnTideExploited vulnerabilities, by vendor. Data as of 28 Oct 2026.
Known exploitedIn CISA's KEV catalog since 16 October 2023Ransomware use: unknown
Cisco IOS XE Web UI

CVE-2023-20198: Cisco IOS XE Web UI Privilege Escalation Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 16 Oct 2023, the same day the CVE record was published.

How likely is exploitation in the next 30 days?
99.6%

EPSS score, percentile 99.9 of all scored records

How severe?
10.0 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline 20 Oct 2023. Verify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. Full text

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • 16.1.1
  • 16.1.2
  • 16.1.3
  • 16.2.1
  • 16.2.2
  • 16.3.1

and 6 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

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.

CISA due date for this action: 20 October 2023.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Cisco Cisco IOS XE Software
StatusVersions
Affected16.1.1
Affected16.1.2
Affected16.1.3
Affected16.2.1
Affected16.2.2
Affected16.3.1
Affected16.3.2
Affected16.3.3
Affected16.3.1a
Affected16.3.4
Affected16.3.5
Affected16.3.5b

And 174 more version entries in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Cisco IOS XE Web UI contains a privilege escalation vulnerability in the web user interface that could allow a remote, unauthenticated attacker to create an account with privilege level 15 access. The attacker can then use that account to gain control of the affected device.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

  • CISA added CVE-2023-20198 to its Known Exploited Vulnerabilities (KEV) catalog on 16 Oct 2023.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 20 Oct 2023.
  • The CVE record was published on 16 Oct 2023, the same day it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 10.0 (Critical), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 99.6% (percentile 99.9), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
16 Oct 2023CVE record published
16 Oct 2023Added to CISA KEV
20 Oct 2023CISA due date for the required action
21 Oct 2025CVE record last updated

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