What it is
CVE-2023-20198 is an unauthenticated vulnerability affecting Cisco IOS XE Software. Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software....
Vulnerability report
Active exploitation observed
Confirmed confidence
In CISA KEV
CVE-2023-20198
Cisco IOS XE Software
Cisco IOS XE Software · 16.1.1
- Severity
- CVSS 10.0 · Critical
- Confidence
- Confirmed
- Exploit status
- Observed in sensors
- EPSS
- 99.6%
- First observed
- 12 Jun 2026
- Last observed
- 08 Oct 2026
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Listed in CISA KEV. Also confirmed by third-party sources.
Who is affected?
Cisco IOS XE Software 16.1.1.
What should we do?
Patch immediately, validate internet-facing exposure, and monitor for matching requests.
Overview
Cisco IOS XE Software
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.
Vendor
Product
Affected
Status
Cisco
Affected
Cisco IOS XE Software
16.1.1
16.1.2
16.1.3
16.2.1
16.2.2
16.3.1
16.3.2
16.3.3
16.3.1a
16.3.4
16.3.5
16.3.5b
16.3.6
16.3.7
16.3.8
16.3.9
16.3.10
16.3.11
16.4.1
16.4.2
16.4.3
16.5.1
16.5.1a
16.5.1b
16.5.2
16.5.3
16.6.1
16.6.2
16.6.3
16.6.4
16.6.5
16.6.4a
16.6.5a
16.6.6
16.6.7
16.6.8
16.6.9
16.6.10
16.7.1
16.7.1a
16.7.1b
16.7.2
16.7.3
16.7.4
16.8.1
16.8.1a
16.8.1b
16.8.1s
16.8.1c
16.8.1d
16.8.2
16.8.1e
16.8.3
16.9.1
16.9.2
16.9.1a
16.9.1b
16.9.1s
16.9.3
16.9.4
16.9.3a
16.9.5
16.9.5f
16.9.6
16.9.7
16.9.8
16.10.1
16.10.1a
16.10.1b
16.10.1s
16.10.1c
16.10.1e
16.10.1d
16.10.2
16.10.1f
16.10.1g
16.10.3
16.11.1
16.11.1a
16.11.1b
16.11.2
16.11.1s
16.12.1
16.12.1s
16.12.1a
16.12.1c
16.12.1w
16.12.2
16.12.1y
16.12.2a
16.12.3
16.12.8
16.12.2s
16.12.1x
16.12.1t
16.12.4
16.12.3s
16.12.3a
16.12.4a
16.12.5
16.12.6
16.12.1z1
16.12.5a
16.12.5b
16.12.1z2
16.12.6a
16.12.7
16.12.9
16.12.10
17.1.1
17.1.1a
17.1.1s
17.1.1t
17.1.3
17.2.1
17.2.1r
17.2.1a
17.2.1v
17.2.2
17.2.3
17.3.1
17.3.2
17.3.3
17.3.1a
17.3.1w
17.3.2a
17.3.1x
17.3.1z
17.3.4
17.3.5
17.3.4a
17.3.6
17.3.4b
17.3.4c
17.3.5a
17.3.5b
17.3.7
17.3.8
17.4.1
17.4.2
17.4.1a
17.4.1b
17.4.2a
17.5.1
17.5.1a
17.5.1b
17.5.1c
17.6.1
17.6.2
17.6.1w
17.6.1a
17.6.1x
17.6.3
17.6.1y
17.6.1z
17.6.3a
17.6.4
17.6.1z1
17.6.5
17.6.6
17.7.1
17.7.1a
17.7.1b
17.7.2
17.10.1
17.10.1a
17.10.1b
17.8.1
17.8.1a
17.9.1
17.9.1w
17.9.2
17.9.1a
17.9.1x
17.9.1y
17.9.3
17.9.2a
17.9.1x1
17.9.3a
17.9.4
17.9.1y1
17.11.1
17.11.1a
17.12.1
17.12.1a
17.11.99SW
Affected
- Published
- 16 Oct 2023
- Exploitation Reported
- 16 Oct 2023
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
edge
nuclei_scanner
ios
nessus_scanner
metasploit
cisa
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2023-20198
- cisco-sa-iosxe-webui-privesc-j22SaA4z sec.cloudapps.cisco.com · CVE Record https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurity...
Exploitation evidence
Why Previdian marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CISA
A trusted third party reported exploitation.
Active exploitation observed
Previdian sensor
Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.
Proof of concept available
GitHub
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the Previdian Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2023-10-16 00:00 UTC |
| The Shadowserver | 2026-06-01 00:00 UTC |
| Tenable Blog | 2026-06-02 14:20 UTC |
| Previdian Sensors | 2026-07-07 13:59 UTC |
Operational indicators for this CVE are listed under Detection.
Sensor telemetry
First-party evidence of exploitation activity
Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.
135
Attempts observed
17
Unique attacker IPs
12
Attacker countries
BG · CH · DE · FR · GB · JP · KW · NL · SC · TM · US · YE
29
Sensors observed
CVE-2023-20198 exploitation attempts over the last 89 days
Daily events observed by Previdian sensors
Updated 09 Oct 2026
13 Jul
31 Jul
18 Aug
5 Sep
9 Oct
First observed 12 Jun 2026 · Last observed 08 Oct 2026
Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- User-Agents
- Callback hosts
- 5
- 3
- 0
Request targets and User-Agents available in Pro. Callback host details available in Enterprise.
Scanner coverage
Metasploit template detected 28 Apr 2025.
View Metasploit template (opens in new tab)Virtual patch status
No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Attacker IP Indicators
Attacker IP indicators observed · available in Pro and Enterprise.
Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.
Learn about Pro API accessScanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Metasploit | https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/misc/cisco_ios_xe_rce.rb | 28 Apr 2025 |
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-20198.yaml | 25 Apr 2025 |
| Nessus | https://www.tenable.com/plugins/nessus/184452 | 06 Nov 2023 |
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
10.0
Critical
Potential damage if exploited. Separate from whether attackers are using it.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS
99.6%
Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.
Weaknesses
Recent mention · Tenable Blog
Inside the customer environment: Where threat actors, vulnerabilities, and exposed assets intersect
Tenable Research has developed a graph-based model linking 600+ threat groups to real-world customer exposures. It reveals which vulnerabilities sit at the intersection of severity, active exploitation, and organizational risk.Key takeawaysThe "patch everything" strategy is...
Read full advisoryAll Mentions
Recent mention · Tenable Blog
Inside the customer environment: Where threat actors, vulnerabilities, and exposed assets intersectTenable Blog · 27 May 2026
Tenable Research has developed a graph-based model linking 600+ threat groups to real-world customer exposures. It reveals which vulnerabilities sit at the intersection of severity, active exploitation, and organizational risk.Key takeawaysThe "patch everything" strategy is dead: Vulnerability prioritization based on exploitation risk offers a path forward. A directed graph model linking 600+ threat actors to vulnerabilities in 7,800 customer environments reveals that 68% of organizations carry at least one CVE previously exploited by a named adversary, and 321 tracked threat groups can...
Recent mention · The Hacker News
China-linked Salt Typhoon Exploits Critical Cisco Vulnerability to Target Canadian TelecomThe Hacker News · 24 Jun 2025
The Canadian Centre for Cyber Security and the U.S. Federal Bureau of Investigation (FBI) have issued an advisory warning of cyber attacks mounted by the China-linked Salt Typhoon actors to breach major global telecommunications providers as part of a cyber espionage campaign. The attackers exploited a critical Cisco IOS XE software (CVE-2023-20198, CVSS score: 10.0) to access configuration
Recent mention · Tenable Blog
Cybersecurity Snapshot: U.K. NCSC’s Best Cyber Advice on AI Security, the Quantum Threat, API Risks, Mobile Malware and MoreTenable Blog · 09 May 2025
In this special edition of the Cybersecurity Snapshot, we bring you some of the most valuable guidance offered by the U.K. National Cyber Security Centre (NCSC) in the past 18 months. Check out best practices, recommendations and insights on protecting your AI systems, APIs and mobile devices, as well as on how to prep for post-quantum cryptography, and more.In case you missed it, here are six NCSC recommendations to help your organization fine-tune its cybersecurity strategy and operations.1 - How to migrate to quantum-resistant cryptographyIs your organization planning to adopt...
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
Cisco IOS XE Web UI - Command Injection
nuclei · Created Unknown
Timeline
From disclosure to observed exploitation
-
14:20 UTC
Public PoC available
Public proof-of-concept code published
-
00:33 UTC
Indicators of compromise added (24)
Indicators of compromise recorded
-
00:33 UTC
Observed by Previdian sensors
Evidence-backed exploitation signal
-
14:20 UTC
KEV confirmed by Tenable Blog
Exploitation attested by an external source
-
00:00 UTC
KEV confirmed by The Shadowserver
Exploitation attested by an external source
-
15:02 UTC
Metasploit module available
Exploit module available
-
00:00 UTC
Nuclei template available
Scanner coverage available
-
18:46 UTC
Nessus plugin available
Scanner coverage available
-
15:12 UTC
CVE published
Vulnerability disclosed publicly
-
00:00 UTC
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
18:47 UTC
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2023-20198
Free JSON includes basic KEV fields{
"cve_id": "CVE-2023-20198",
"confidence": "Confirmed",
"cvss_score": 10.0,
"cvss_estimated": false,
"epss_score": 0.99571,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": true
},
"sensor_telemetry": { "attempts": 135, "sensors": 29 }
}