CVE-2026-20010 vulnerability in Cisco Products
Published on February 25, 2026

Cisco Nexus 3000 and 9000 Series Switches Link Layer Discovery Protocol Denial of Service Vulnerability
A vulnerability in the Link Layer Discovery Protocol (LLDP) feature of Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause the LLDP process to restart, which could cause an affected device to reload unexpectedly. This vulnerability is due to improper handling of specific fields in an LLDP frame. An attacker could exploit this vulnerability by sending a crafted LLDP packet to an interface of an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition. Note: LLDP is a Layer 2 link protocol. To exploit this vulnerability, an attacker would need to be directly connected to an interface of an affected device, either physically or logically (for example, through a Layer 2 Tunnel configured to transport the LLDP protocol).

NVD

Vulnerability Analysis

Exploitation:

NONE

Automatable:

NO

Technical Impact:

PARTIAL

Attack Vector:

ADJACENT_NETWORK

Attack Complexity:

LOW

Privileges Required:

NONE

User Interaction:

NONE

Scope:

CHANGED

Confidentiality Impact:

NONE

Integrity Impact:

NONE

Availability Impact:

HIGH

Weakness Type

Buffer Access with Incorrect Length Value

The software uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer. When the length value exceeds the size of the destination, a buffer overflow could occur.

Products Associated with CVE-2026-20010

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Cisco Nx Os

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Affected Versions

• Version 10.3(1) is affected.
• Version 10.3(2) is affected.
• Version 10.3(3) is affected.
• Version 10.4(1) is affected.
• Version 10.3(99w) is affected.
• Version 10.3(3w) is affected.
• Version 10.3(99x) is affected.
• Version 10.3(3o) is affected.
• Version 10.3(4) is affected.
• Version 10.3(3p) is affected.
• Version 10.3(4a) is affected.
• Version 10.4(2) is affected.
• Version 10.3(3q) is affected.
• Version 10.3(3x) is affected.
• Version 10.3(4g) is affected.
• Version 10.3(3r) is affected.
• Version 10.3(4h) is affected.

• Version 16.0(2h) is affected.
• Version 16.0(2j) is affected.
• Version 16.0(3d) is affected.
• Version 16.0(3e) is affected.
• Version 16.0(4c) is affected.
• Version 16.0(5h) is affected.
• Version 16.0(3g) is affected.
• Version 16.0(5j) is affected.
• Version 16.0(6c) is affected.
• Version 16.1(1f) is affected.
• Version 16.0(7e) is affected.
• Version 16.0(8e) is affected.
• Version 16.0(8f) is affected.
• Version 16.1(2f) is affected.
• Version 16.1(2g) is affected.
• Version 16.0(9c) is affected.
• Version 16.1(3f) is affected.
• Version 16.0(9d) is affected.
• Version 16.0(6h) is affected.
• Version 16.0(8h) is affected.
• Version 16.1(3g) is affected.

• Version 4.3(4e) is affected.
• Version 4.3(6b) is affected.
• Version 4.3(4c) is affected.
• Version 4.3(4f) is affected.
• Version 4.3(6d) is affected.
• Version 4.3(5e) is affected.
• Version 4.3(4d) is affected.
• Version 4.3(4b) is affected.
• Version 4.3(5a) is affected.
• Version 4.3(5c) is affected.
• Version 4.3(5d) is affected.
• Version 4.3(6c) is affected.
• Version 4.3(6a) is affected.

Exploit Probability