Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability (Cisco Cisco IOS XR Software)

CVE-2026-20074
HIGH 7.4

At a glance

Source
NVD
EPSS
EPSS 0.16 % · percentile 5 ()
State
PUBLISHED
Published
Updated
Assigner
cisco
NVD status
Analyzed

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.  

Weaknesses (CWE)

  • CWE-1287 — Improper Validation of Specified Type of Input

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.4CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hcisco
CVSS 3.1HIGH 7.4CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HNVD · psirt@cisco.com (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Cisco · Cisco IOS XR Softwareaffected 7.8.1 ; affected 7.9.1 ; affected 7.10.1 ; affected 7.8.2 ; affected 7.8.22 ; affected 7.9.2

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD