CVE-2026-20074

HIGH EPSS 5.6%
Published Mar 11, 20263mo ago · Modified Mar 12, 20263mo ago
7.4 CVSS 3.1
High
Find Similar
Published Mar 11, 2026 3mo ago
Last Modified Mar 12, 2026 3mo ago

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.  

CVSS Details

Base Score
7.4
Exploitability
2.8
Impact
4.0
Vector string
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

Threat Intelligence

EPSS Exploit Probability
5.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-1287

References 1

  • sec.cloudapps.cisco.com https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.