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TI-2026-16288 Aliases CVE-2026-20074GHSA-95m8-qgxc-hcqx

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

Priority LOW 32CWE-1287Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

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.  

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00179 7th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco IOS XR Software7.8.1; 7.9.1; 7.10.1; 7.8.2; 7.8.22; 7.9.2; 7.11.1; 7.9.21; 7.10.2; 24.1.1; 7.11.2; 24.2.1; 24.1.2; 24.2.11; 24.3.1; 24.4.1; 24.2.2; 7.8.23; 7.11.21; 24.2.20; 24.3.2; 24.4.10; 25.1.1; 24.4.2; 24.3.20; 24.4.15; 25.2.1; 25.1.2; 24.3.30; 24.4.30; 24.2.21; 25.2.15—No fix listedCNA
  • Cisco IOS XR Software VendorCisco Affected 7.8.1; 7.9.1; 7.10.1; 7.8.2; 7.8.22; 7.9.2; 7.11.1; 7.9.21; 7.10.2; 24.1.1; 7.11.2; 24.2.1; 24.1.2; 24.2.11; 24.3.1; 24.4.1; 24.2.2; 7.8.23; 7.11.21; 24.2.20; 24.3.2; 24.4.10; 25.1.1; 24.4.2; 24.3.20; 24.4.15; 25.2.1; 25.1.2; 24.3.30; 24.4.30; 24.2.21; 25.2.15 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*7.8.0 to before 25.2.2VulnerableCisco
cpe:2.3:o:cisco:ios_xr:25.3.0:*:*:*:*:*:*:*25.3.0VulnerableCisco
  • cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* Versions 7.8.0 to before 25.2.2 Vulnerable ·Cisco
  • cpe:2.3:o:cisco:ios_xr:25.3.0:*:*:*:*:*:*:* Versions 25.3.0 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-20074
  2. 2026-10-03 Alias added: GHSA-95m8-qgxc-hcqx

References

Advisory 1

  • TI-2020-02680 Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2018-00135 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.8
  • TI-2020-03113 Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities KEVCVSS 3.1HIGH 8.6
  • TI-2020-03110 Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability KEVCVSS 3.1HIGH 8.6
  • TI-2018-00142 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.0
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
See all 199 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences