CVE-2025-20140 [High] | Denial of Service in Ios Xe

A vulnerability in the Wireless Network Control daemon (wncd) of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, adjacent wireless attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper memory management. An attacker could exploit this vulnerability by sending a series of IPv6 network requests from an associated wireless IPv6 client to an affected device. To associate a client to a device, an attacker may first need to authenticate to the network, or associate freely in the case of a configured open network. A successful exploit could allow the attacker to cause the wncd process to consume available memory and eventually cause the device to stop responding, resulting in a DoS condition.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.10%	0.20%	+0.10%
2	2026-03-03	0.01%	0.10%	+0.09%
3	2025-05-08	—	0.01%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.10%

0.20%

+0.10%

2026-03-03

0.01%

0.10%

+0.09%

2025-05-08

—

0.01%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.4	3.1	HIGH	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	4.0	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.4

3.1

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

4.0

[email protected]

Affected software / configurations for CVE-2025-20140

Vendor	Product	Version	Raw CPE
cisco	ios_xe	16.4.1	cpe:2.3:o:cisco:ios_xe:16.4.1:::::::*
cisco	ios_xe	16.4.2	cpe:2.3:o:cisco:ios_xe:16.4.2:::::::*
cisco	ios_xe	16.4.3	cpe:2.3:o:cisco:ios_xe:16.4.3:::::::*
cisco	ios_xe	16.5.1	cpe:2.3:o:cisco:ios_xe:16.5.1:::::::*
cisco	ios_xe	16.5.1a	cpe:2.3:o:cisco:ios_xe:16.5.1a:::::::*
cisco	ios_xe	16.5.1b	cpe:2.3:o:cisco:ios_xe:16.5.1b:::::::*
cisco	ios_xe	16.5.2	cpe:2.3:o:cisco:ios_xe:16.5.2:::::::*
cisco	ios_xe	16.5.3	cpe:2.3:o:cisco:ios_xe:16.5.3:::::::*
cisco	ios_xe	16.6.1	cpe:2.3:o:cisco:ios_xe:16.6.1:::::::*
cisco	ios_xe	16.6.2	cpe:2.3:o:cisco:ios_xe:16.6.2:::::::*
cisco	ios_xe	16.6.3	cpe:2.3:o:cisco:ios_xe:16.6.3:::::::*
cisco	ios_xe	16.6.4	cpe:2.3:o:cisco:ios_xe:16.6.4:::::::*
cisco	ios_xe	16.6.4a	cpe:2.3:o:cisco:ios_xe:16.6.4a:::::::*
cisco	ios_xe	16.6.5	cpe:2.3:o:cisco:ios_xe:16.6.5:::::::*
cisco	ios_xe	16.6.5a	cpe:2.3:o:cisco:ios_xe:16.6.5a:::::::*
cisco	ios_xe	16.6.6	cpe:2.3:o:cisco:ios_xe:16.6.6:::::::*
cisco	ios_xe	16.6.7	cpe:2.3:o:cisco:ios_xe:16.6.7:::::::*
cisco	ios_xe	16.6.8	cpe:2.3:o:cisco:ios_xe:16.6.8:::::::*
cisco	ios_xe	16.6.9	cpe:2.3:o:cisco:ios_xe:16.6.9:::::::*
cisco	ios_xe	16.6.10	cpe:2.3:o:cisco:ios_xe:16.6.10:::::::*
cisco	ios_xe	16.7.1	cpe:2.3:o:cisco:ios_xe:16.7.1:::::::*
cisco	ios_xe	16.7.1a	cpe:2.3:o:cisco:ios_xe:16.7.1a:::::::*
cisco	ios_xe	16.7.1b	cpe:2.3:o:cisco:ios_xe:16.7.1b:::::::*
cisco	ios_xe	16.7.2	cpe:2.3:o:cisco:ios_xe:16.7.2:::::::*
cisco	ios_xe	16.7.3	cpe:2.3:o:cisco:ios_xe:16.7.3:::::::*
cisco	ios_xe	16.7.4	cpe:2.3:o:cisco:ios_xe:16.7.4:::::::*
cisco	ios_xe	16.8.1	cpe:2.3:o:cisco:ios_xe:16.8.1:::::::*
cisco	ios_xe	16.8.1a	cpe:2.3:o:cisco:ios_xe:16.8.1a:::::::*
cisco	ios_xe	16.8.1b	cpe:2.3:o:cisco:ios_xe:16.8.1b:::::::*
cisco	ios_xe	16.8.1c	cpe:2.3:o:cisco:ios_xe:16.8.1c:::::::*
cisco	ios_xe	16.8.1d	cpe:2.3:o:cisco:ios_xe:16.8.1d:::::::*
cisco	ios_xe	16.8.1e	cpe:2.3:o:cisco:ios_xe:16.8.1e:::::::*
cisco	ios_xe	16.8.1s	cpe:2.3:o:cisco:ios_xe:16.8.1s:::::::*
cisco	ios_xe	16.8.2	cpe:2.3:o:cisco:ios_xe:16.8.2:::::::*
cisco	ios_xe	16.8.3	cpe:2.3:o:cisco:ios_xe:16.8.3:::::::*
cisco	ios_xe	16.9.1	cpe:2.3:o:cisco:ios_xe:16.9.1:::::::*
cisco	ios_xe	16.9.1a	cpe:2.3:o:cisco:ios_xe:16.9.1a:::::::*
cisco	ios_xe	16.9.1b	cpe:2.3:o:cisco:ios_xe:16.9.1b:::::::*
cisco	ios_xe	16.9.1s	cpe:2.3:o:cisco:ios_xe:16.9.1s:::::::*
cisco	ios_xe	16.9.2	cpe:2.3:o:cisco:ios_xe:16.9.2:::::::*
cisco	ios_xe	16.9.3	cpe:2.3:o:cisco:ios_xe:16.9.3:::::::*
cisco	ios_xe	16.9.3a	cpe:2.3:o:cisco:ios_xe:16.9.3a:::::::*
cisco	ios_xe	16.9.4	cpe:2.3:o:cisco:ios_xe:16.9.4:::::::*
cisco	ios_xe	16.9.5	cpe:2.3:o:cisco:ios_xe:16.9.5:::::::*
cisco	ios_xe	16.9.5f	cpe:2.3:o:cisco:ios_xe:16.9.5f:::::::*
cisco	ios_xe	16.9.6	cpe:2.3:o:cisco:ios_xe:16.9.6:::::::*
cisco	ios_xe	16.9.7	cpe:2.3:o:cisco:ios_xe:16.9.7:::::::*
cisco	ios_xe	16.9.8	cpe:2.3:o:cisco:ios_xe:16.9.8:::::::*
cisco	ios_xe	16.10.1	cpe:2.3:o:cisco:ios_xe:16.10.1:::::::*
cisco	ios_xe	16.10.1a	cpe:2.3:o:cisco:ios_xe:16.10.1a:::::::*
cisco	ios_xe	16.10.1b	cpe:2.3:o:cisco:ios_xe:16.10.1b:::::::*
cisco	ios_xe	16.10.1c	cpe:2.3:o:cisco:ios_xe:16.10.1c:::::::*
cisco	ios_xe	16.10.1d	cpe:2.3:o:cisco:ios_xe:16.10.1d:::::::*
cisco	ios_xe	16.10.1e	cpe:2.3:o:cisco:ios_xe:16.10.1e:::::::*
cisco	ios_xe	16.10.1f	cpe:2.3:o:cisco:ios_xe:16.10.1f:::::::*
cisco	ios_xe	16.10.1g	cpe:2.3:o:cisco:ios_xe:16.10.1g:::::::*
cisco	ios_xe	16.10.1s	cpe:2.3:o:cisco:ios_xe:16.10.1s:::::::*
cisco	ios_xe	16.10.2	cpe:2.3:o:cisco:ios_xe:16.10.2:::::::*
cisco	ios_xe	16.10.3	cpe:2.3:o:cisco:ios_xe:16.10.3:::::::*
cisco	ios_xe	16.11.1	cpe:2.3:o:cisco:ios_xe:16.11.1:::::::*
cisco	ios_xe	16.11.1a	cpe:2.3:o:cisco:ios_xe:16.11.1a:::::::*
cisco	ios_xe	16.11.1b	cpe:2.3:o:cisco:ios_xe:16.11.1b:::::::*
cisco	ios_xe	16.11.1s	cpe:2.3:o:cisco:ios_xe:16.11.1s:::::::*
cisco	ios_xe	16.11.2	cpe:2.3:o:cisco:ios_xe:16.11.2:::::::*
cisco	ios_xe	16.12.1	cpe:2.3:o:cisco:ios_xe:16.12.1:::::::*
cisco	ios_xe	16.12.1a	cpe:2.3:o:cisco:ios_xe:16.12.1a:::::::*
cisco	ios_xe	16.12.1c	cpe:2.3:o:cisco:ios_xe:16.12.1c:::::::*
cisco	ios_xe	16.12.1s	cpe:2.3:o:cisco:ios_xe:16.12.1s:::::::*
cisco	ios_xe	16.12.1t	cpe:2.3:o:cisco:ios_xe:16.12.1t:::::::*
cisco	ios_xe	16.12.1w	cpe:2.3:o:cisco:ios_xe:16.12.1w:::::::*
cisco	ios_xe	16.12.1x	cpe:2.3:o:cisco:ios_xe:16.12.1x:::::::*
cisco	ios_xe	16.12.1y	cpe:2.3:o:cisco:ios_xe:16.12.1y:::::::*
cisco	ios_xe	16.12.1z1	cpe:2.3:o:cisco:ios_xe:16.12.1z1:::::::*
cisco	ios_xe	16.12.1z2	cpe:2.3:o:cisco:ios_xe:16.12.1z2:::::::*
cisco	ios_xe	16.12.2	cpe:2.3:o:cisco:ios_xe:16.12.2:::::::*
cisco	ios_xe	16.12.2a	cpe:2.3:o:cisco:ios_xe:16.12.2a:::::::*
cisco	ios_xe	16.12.2s	cpe:2.3:o:cisco:ios_xe:16.12.2s:::::::*
cisco	ios_xe	16.12.3	cpe:2.3:o:cisco:ios_xe:16.12.3:::::::*
cisco	ios_xe	16.12.3a	cpe:2.3:o:cisco:ios_xe:16.12.3a:::::::*
cisco	ios_xe	16.12.3s	cpe:2.3:o:cisco:ios_xe:16.12.3s:::::::*

References for CVE-2025-20140

URL	Tags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-wncd-p6Gvt6HL	Vendor Advisory

URL

CVE-2025-20140

Exploit prediction scoring system (EPSS) score for CVE-2025-20140

Common vulnerability scoring system (CVSS) metrics for CVE-2025-20140

Weakness enumeration for CVE-2025-20140

Affected software / configurations for CVE-2025-20140

References for CVE-2025-20140