SB2026031202 - Denial of service in Cisco IOS XR IS-IS feature
Published: March 12, 2026
Security Bulletin ID
SB2026031202
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Adjecent network
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper validation of specified type of input (CVE-ID: CVE-2026-20074)
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.