QwikSec

Security Database

CVE

CWE

Training

CVE Database
/

CVE-2026-20074

Back to search

CVE-2026-20074

Published: Mar 11, 2026

Modified: Mar 11, 2026

PUBLISHED

CVSS v3.1

7.4

HIGH

Description

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.  

VendorProductVersions

Cisco

Cisco IOS XR Software

affected
7.8.1
affected
7.9.1
affected
7.10.1
affected
7.8.2
affected
7.8.22

+27 more versions

Weaknesses (CWE)

CWE-1287

CVSS v3.1 Details

CVSS v3.1 Vector

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

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

References

Security Training

Train your team to recognize and prevent security threats with our comprehensive security awareness program.

Start Training

Vulnerability Scanning

Discover vulnerabilities in your applications and infrastructure before attackers do.

Scan Now