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TI-2019-01538 Aliases CVE-2019-1918GHSA-29rc-5w3j-4hr7

Cisco IOS XR Software Intermediate System–to–Intermediate System Denial of Service Vulnerability

Priority LOW 33CWE-20Published · 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 · NVD. Fix status from CNA.

Summary

A vulnerability in the implementation of Intermediate System–to–Intermediate System (IS–IS) routing protocol functionality in Cisco IOS XR Software could allow an unauthenticated attacker who is in the same IS-IS area to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of IS–IS link-state protocol data units (PDUs). An attacker could exploit this vulnerability by sending specific link-state PDUs to an affected system to be processed. A successful exploit could allow the attacker to cause incorrect calculations used in the weighted remote shared risk link groups (SRLG) or in the IGP Flexible Algorithm. It could also cause tracebacks to the logs or potentially cause the receiving device to crash the IS–IS process, resulting in a DoS condition.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00525 44th 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 Softwareall versions—No fix listedCNA
  • Cisco IOS XR Software VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*6.5.2 to before 6.6.3VulnerableCisco
cpe:2.3:o:cisco:carrier_routing_system:6.5.1:*:*:*:*:*:*:*6.5.1VulnerableCisco
cpe:2.3:o:cisco:carrier_routing_system:6.5.3:*:*:*:*:*:*:*6.5.3VulnerableCisco
  • cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* Versions 6.5.2 to before 6.6.3 Vulnerable ·Cisco
  • cpe:2.3:o:cisco:carrier_routing_system:6.5.1:*:*:*:*:*:*:* Versions 6.5.1 Vulnerable ·Cisco
  • cpe:2.3:o:cisco:carrier_routing_system:6.5.3:*:*:*:*:*:*:* Versions 6.5.3 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2019-1918
  2. 2026-10-03 Alias added: GHSA-29rc-5w3j-4hr7

References

Advisory 1

  • TI-2018-00106 Memory corruption in Cisco IOS XR CVSS 3.0HIGH 8.6
  • TI-2015-00573 Cisco IOS XR 5.0.1 and 5.2.1 on Network Convergence System (NCS) 6000 devices and 5.1.3… CVSS 2.0HIGH 7.1
  • TI-2019-01531 Cisco IOS XR Software Intermediate System to Intermediate System Denial of Service Vulnerability CVSS 3.1HIGH 7.4
  • TI-2012-01192 Cisco Carrier Routing System (CRS) 3.9, 4.0, and 4.1 allows remote attackers to bypass… CVSS 3.1MEDIUM 5.8
  • TI-2013-00961 Cisco Carrier Routing System (CRS) allows remote attackers to cause a denial of service… CVSS 2.0MEDIUM 5.0
  • TI-2011-02911 Cisco Carrier Routing System 3.9.1 allows remote attackers to cause a denial of service… CVSS 2.0MEDIUM 5.0
See all 7 →

Sources

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