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Cisco IOS XE Web UI Privilege Escalation Vulnerability

Exploited · KEV 2023-10-16Metasploit moduleCVE-2023-20198CWE-420

Exploited since 2023-10-16. 2 of 8 rule sources name it; Cloudflare blocks by default. Our CRS test: blocked.

Edge rules
2/8
Our test
Blocked
CVSS
10.0
EPSS
99.6% Top 0.1%
Posts, 14d
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Published
2023-10-16
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… More

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.

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Severity, decoded

CVSS 3.1
Critical · 10.0 / 10

Exploitable over the network, with no privileges and no user interaction, leading to full loss of confidentiality, integrity and availability, and the impact can reach components beyond the vulnerable one.

Over the internetNo login neededNo user actionWorks reliablySpreads beyond the appFull compromise
How the score is built8 metrics
  • Attack vectorAn attacker can reach it over the internet; no access to your network needed.
    Network
  • Attack complexityNo special conditions are needed; the attack works reliably.
    Low
  • Privileges requiredNo account or login is needed.
    None
  • User interactionNo one has to click or open anything; the attack works on its own.
    None
  • ScopeThe attack can spread beyond the vulnerable component to other parts of the system.
    Changed
  • Confidentiality impactAn attacker can read all data the affected component holds, or the most sensitive parts of it.
    High
  • Integrity impactAn attacker can change any data or files the affected component protects.
    High
  • Availability impactAn attacker can take the component down completely or keep it from serving anyone.
    High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA's assessmentSSVC, from the CVE record
ExploitationActive

Attackers are exploiting this in the wild.

AutomatableYes

Attackers can script the attack end to end and hit many targets at once.

Technical impactTotal

A successful attack gives full control over the affected software or all of its data.

Public exploits

4 found
3 Metasploit0 Exploit-DB1 Scanner template0 GitHub PoCs

Links are to third-party code: never run it outside an isolated lab.

Timeline

  1. 2023-10-16
    CVE published
    CVE List
  2. 2023-10-16
    Added to CISA KEV
    Confirmed exploitation in the wild
  3. 2023-10-16
    Metasploit module published
    Cisco IOX XE unauthenticated Command Line Interface (CLI) execution
  4. 2023-12-12
    F5 ships a rule
    Cisco IOS XE Authorization Bypass
  5. 2025-03-10
    Cloudflare ships a rule
    Cisco IOS XE - Information Disclosure - CVE:CVE-2023-20198
  6. 2026-11-02
    Our test: OWASP Core Rule Set blocked it
    paranoia level 1, anomaly threshold 5, default CRS settings
  7. 2026-11-02
    Our test: OWASP Core Rule Set blocked it
    paranoia level 2, anomaly threshold 5, default CRS settings

Social

2026-10-20: 0 posts2026-10-21: 0 posts2026-10-22: 0 posts2026-10-23: 0 posts2026-10-24: 0 posts2026-10-25: 0 posts2026-10-26: 0 posts2026-10-27: 0 posts2026-10-28: 0 posts2026-10-29: 0 posts2026-10-30: 0 posts2026-10-31: 0 posts2026-11-01: 0 posts2026-11-02: 0 posts

No posts seen yet on X, Bluesky, Mastodon, Hacker News or GitHub.

Vendor statements

Quoted
CloudflareWAF Managed Rules2 quotesBlocks by default

First rule 2025-03-10, 511 days after the CVE was published.

2025-03-10New rule…259073d5Default: BlockSource
Cisco IOS XE - Information Disclosure - CVE:CVE-2023-20198. Previous action: Log. New action: Block. This is a New Detection
2025-03-17Updated…0ad61fa7Default: DisabledSource
Cisco IOS XE - Remote Code Execution - CVE:CVE-2023-20198. Previous action: Log. New action: Disabled. Fixed action value in changelog; no rule changes.
AWSAWS WAF Managed RulesNo public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. AWS often describes a vulnerability without naming its CVE (for example "Log4j"). We count only entries that name the CVE, so AWS coverage is understated.

Microsoft AzureFront Door and Application Gateway WAF (DRS)No public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. The rule tables name CVEs but carry no dates, so Azure is left out of every time-to-rule figure.

Google CloudCloud Armor preconfigured WAF rulesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

FastlyNext-Gen WAF virtual patchesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

F5Attack signatures (Distributed Cloud WAF)1 quoteRule published

First rule 2023-12-12, 57 days after the CVE was published.

2023-12-12New rule200013068Source
Added: signature 200013068 "Cisco IOS XE Authorization Bypass" (Authentication/Authorization Attacks, risk High), systems: Cisco. References: CVE-2023-20198.
AkamaiApp & API Protector (Adaptive Security Engine)No public source

This vendor publishes no machine-readable rule changelog we can check.

OWASP CRSCore Rule Set (open source, used inside many WAFs)No public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. CRS rarely names CVEs: it relies on generic detections. Our own lab measures what it actually blocks.