CVE-2019-1918
CVE-2019-1918 is a high-severity vulnerability in Cisco Ios Xr with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-682.
Key facts
- Severity: High (CVSS 3.x base score 7.4)
- CVSS v2: 6.1
- EPSS exploit prediction: 1% (41st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-682
- Affected product: Cisco Ios Xr
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2019-1918?
- 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.
- How severe is CVE-2019-1918?
- CVE-2019-1918 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2019-1918 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2019-1918?
- CVE-2019-1918 primarily affects Cisco Ios Xr. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2019-1918?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2019-1918 published?
- CVE-2019-1918 was published on 2019-08-07 and last updated on 2026-06-17.
References
Affected products (3)
- cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:carrier_routing_system:6.5.1:*:*:*:*:*:*:*
- cpe:2.3:o:cisco:carrier_routing_system:6.5.3:*:*:*:*:*:*:*
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