CVE-2019-1750 [High] | Input Validation Bypass in Ios Xe

A vulnerability in the Easy Virtual Switching System (VSS) of Cisco IOS XE Software on Catalyst 4500 Series Switches could allow an unauthenticated, adjacent attacker to cause the switches to reload. The vulnerability is due to incomplete error handling when processing Cisco Discovery Protocol (CDP) packets used with the Easy Virtual Switching System. An attacker could exploit this vulnerability by sending a specially crafted CDP packet. An exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.14%	0.71%	+0.57%
2	2025-03-30	0.18%	0.14%	-0.03%
3	2025-03-29	—	0.18%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.14%

0.71%

+0.57%

2025-03-30

0.18%

0.14%

-0.03%

2025-03-29

—

0.18%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.4	3.0	HIGH	`CVSS:3.0/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]
7.4	3.0	HIGH	`CVSS:3.0/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]
6.1	2.0	MEDIUM	`AV:A/AC:L/Au:N/C:N/I:N/A:C` Click to expand Access vector (AV:A) Requires access to an adjacent network segment. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:C) Complete availability impact.	6.5	6.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.4

3.0

HIGH

CVSS:3.0/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]

7.4

3.0

HIGH

CVSS:3.0/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]

6.1

2.0

MEDIUM

AV:A/AC:L/Au:N/C:N/I:N/A:C Click to expand

Access vector (AV:A): Requires access to an adjacent network segment.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:C): Complete availability impact.

6.5

6.9

[email protected]

Affected software / configurations for CVE-2019-1750

Vendor	Product	Version	Raw CPE
cisco	ios_xe	3.6.0ae	cpe:2.3:o:cisco:ios_xe:3.6.0ae:::::::*
cisco	ios_xe	3.6.0be	cpe:2.3:o:cisco:ios_xe:3.6.0be:::::::*
cisco	ios_xe	3.6.0e	cpe:2.3:o:cisco:ios_xe:3.6.0e:::::::*
cisco	ios_xe	3.6.1e	cpe:2.3:o:cisco:ios_xe:3.6.1e:::::::*
cisco	ios_xe	3.6.2ae	cpe:2.3:o:cisco:ios_xe:3.6.2ae:::::::*
cisco	ios_xe	3.6.2e	cpe:2.3:o:cisco:ios_xe:3.6.2e:::::::*
cisco	ios_xe	3.6.3e	cpe:2.3:o:cisco:ios_xe:3.6.3e:::::::*
cisco	ios_xe	3.6.4e	cpe:2.3:o:cisco:ios_xe:3.6.4e:::::::*
cisco	ios_xe	3.6.5ae	cpe:2.3:o:cisco:ios_xe:3.6.5ae:::::::*
cisco	ios_xe	3.6.5be	cpe:2.3:o:cisco:ios_xe:3.6.5be:::::::*
cisco	ios_xe	3.6.5e	cpe:2.3:o:cisco:ios_xe:3.6.5e:::::::*
cisco	ios_xe	3.6.6e	cpe:2.3:o:cisco:ios_xe:3.6.6e:::::::*
cisco	ios_xe	3.6.7ae	cpe:2.3:o:cisco:ios_xe:3.6.7ae:::::::*
cisco	ios_xe	3.6.7be	cpe:2.3:o:cisco:ios_xe:3.6.7be:::::::*
cisco	ios_xe	3.6.7e	cpe:2.3:o:cisco:ios_xe:3.6.7e:::::::*
cisco	ios_xe	3.6.8e	cpe:2.3:o:cisco:ios_xe:3.6.8e:::::::*
cisco	ios_xe	3.6.9e	cpe:2.3:o:cisco:ios_xe:3.6.9e:::::::*
cisco	ios_xe	3.6.10e	cpe:2.3:o:cisco:ios_xe:3.6.10e:::::::*
cisco	ios_xe	3.7.0e	cpe:2.3:o:cisco:ios_xe:3.7.0e:::::::*
cisco	ios_xe	3.7.1e	cpe:2.3:o:cisco:ios_xe:3.7.1e:::::::*
cisco	ios_xe	3.7.2e	cpe:2.3:o:cisco:ios_xe:3.7.2e:::::::*
cisco	ios_xe	3.7.3e	cpe:2.3:o:cisco:ios_xe:3.7.3e:::::::*
cisco	ios_xe	3.8.0e	cpe:2.3:o:cisco:ios_xe:3.8.0e:::::::*
cisco	ios_xe	3.8.1e	cpe:2.3:o:cisco:ios_xe:3.8.1e:::::::*
cisco	ios_xe	3.8.2e	cpe:2.3:o:cisco:ios_xe:3.8.2e:::::::*
cisco	ios_xe	3.8.3e	cpe:2.3:o:cisco:ios_xe:3.8.3e:::::::*
cisco	ios_xe	3.8.4e	cpe:2.3:o:cisco:ios_xe:3.8.4e:::::::*
cisco	ios_xe	3.8.5ae	cpe:2.3:o:cisco:ios_xe:3.8.5ae:::::::*
cisco	ios_xe	3.8.5e	cpe:2.3:o:cisco:ios_xe:3.8.5e:::::::*
cisco	ios_xe	3.8.6e	cpe:2.3:o:cisco:ios_xe:3.8.6e:::::::*
cisco	ios_xe	3.8.7e	cpe:2.3:o:cisco:ios_xe:3.8.7e:::::::*
cisco	ios_xe	3.9.0e	cpe:2.3:o:cisco:ios_xe:3.9.0e:::::::*
cisco	ios_xe	3.9.1e	cpe:2.3:o:cisco:ios_xe:3.9.1e:::::::*
cisco	ios_xe	3.9.2be	cpe:2.3:o:cisco:ios_xe:3.9.2be:::::::*
cisco	ios_xe	3.9.2e	cpe:2.3:o:cisco:ios_xe:3.9.2e:::::::*
cisco	ios_xe	3.10.0ce	cpe:2.3:o:cisco:ios_xe:3.10.0ce:::::::*
cisco	ios_xe	3.10.0e	cpe:2.3:o:cisco:ios_xe:3.10.0e:::::::*
cisco	ios_xe	3.10.1ae	cpe:2.3:o:cisco:ios_xe:3.10.1ae:::::::*
cisco	ios_xe	3.10.1e	cpe:2.3:o:cisco:ios_xe:3.10.1e:::::::*
cisco	ios_xe	3.10.1se	cpe:2.3:o:cisco:ios_xe:3.10.1se:::::::*
cisco	ios_xe	3.10.2e	cpe:2.3:o:cisco:ios_xe:3.10.2e:::::::*
cisco	ios_xe	16.9.2h	cpe:2.3:o:cisco:ios_xe:16.9.2h:::::::*

References for CVE-2019-1750

URL	Tags
http://www.securityfocus.com/bid/107607	Third Party Advisory VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190327-evss	Patch Vendor Advisory

URL

CVE-2019-1750 | Cisco IOS XE Software Catalyst 4500 Cisco Discovery Protocol Denial of Service Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2019-1750

Common vulnerability scoring system (CVSS) metrics for CVE-2019-1750

Weakness enumeration for CVE-2019-1750

Affected software / configurations for CVE-2019-1750

References for CVE-2019-1750