SB2026031202 - Denial of service in Cisco IOS XR IS-IS feature

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Main Vulnerability Database SB2026031202

SB2026031202 - Denial of service in Cisco IOS XR IS-IS feature

Published: March 12, 2026

Security Bulletin ID SB2026031202
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Adjecent network
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper validation of specified type of input (CVE-ID: CVE-2026-20074)

CWE-ID: CWE-1287 - Improper Validation of Specified Type of Input

CVSSv4: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform a denial of service attack.

The vulnerability exists due to improper input validation of ingress IS-IS packets in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature. A remote attacker on the local network can send specially crafted IS-IS packets to an affected device and perform a denial of service attack.


Remediation

Install update from vendor's website.

References