CVE-2023-20202

Device reload via wncd memory exhaustion

Published Sep 27, 2023 · Updated Nov 21, 2024

Denial of service in Cisco IOS XE Software's wncd process allows unauthenticated physically proximate attackers to reload affected devices. The daemon mishandles a series of network requests, consuming available memory until the controller reloads. Affected releases are exposed only on supported Wireless LAN Controllers with mDNS enabled, and the consequence is a service-interrupting reload.

CVSS severity6.1
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco IOS XE Software's wncd process allows unauthenticated physically proximate attackers to reload affected devices. The daemon mishandles a series of network requests, consuming available memory until the controller reloads. Affected releases are exposed only on supported Wireless LAN Controllers with mDNS enabled, and the consequence is a service-interrupting reload.

The record

CVE
CVE-2023-20202
Published
Sep 27, 2023
Updated
Nov 21, 2024
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-789, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 21, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=17.10.1
  2. Affected versionversion=17.10.1a
  3. Affected versionversion=17.10.1b
  4. Affected versionversion=17.9.1
  5. Affected versionversion=17.9.1a
  6. Affected versionversion=17.9.1w
  7. Affected versionversion=17.9.1x
  8. Affected versionversion=17.9.1x1
  9. Affected versionversion=17.9.1y
  10. Affected versionversion=17.9.2
  11. Affected versionversion=17.9.2a

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOS XE Softwareversion=17.10.1; version=17.10.1a; version=17.10.1b; version=17.9.1; version=17.9.1a; version=17.9.1w; version=17.9.1x; version=17.9.1x1; version=17.9.1y; version=17.9.2; version=17.9.2a

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.1Cisco Systems, Inc.CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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