CVE-2025-20241 - CVE House
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Status published High CVE-2025-20241

Cisco Nexus 3000 and 9000 Series Switches IS-IS Protocol <TBD> Denial of Service Vulnerability

Vulnerability Description

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload. This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

Cisco NX-OS Software
Vulnerable Versions:
9.2(3), 7.0(3)I5(2), 6.0(2)A8(7a), 7.0(3)I4(5), 7.0(3)I4(6), 7.0(3)I4(3), 9.2(2v), 7.0(3)I4(7), 7.0(3)I4(1), 7.0(3)I4(8), 7.0(3)I4(2), 6.0(2)A8(11), 9.2(1), 9.2(2t), 9.2(3y), 7.0(3)I4(1t), 7.0(3)I7(6z), 9.3(2), 7.0(3)F3(3), 7.0(3)I7(3z), 7.0(3)IM7(2), 6.0(2)A8(11b), 7.0(3)I7(5a), 7.0(3)I6(1), 7.0(3)I5(3b), 9.2(4), 6.0(2)A8(10), 6.0(2)A8(2), 7.0(3)IC4(4), 7.0(3)F3(3c), 7.0(3)F3(1), 7.0(3)F3(5), 7.0(3)I7(2), 7.0(3)I5(3), 7.0(3)I7(3), 6.0(2)A8(6), 7.0(3)I6(2), 6.0(2)A8(5), 9.3(1), 6.0(2)A8(7), 7.0(3)I7(6), 6.0(2)A8(11a), 7.0(3)I4(8z), 7.0(3)I4(9), 7.0(3)I7(4), 7.0(3)I7(7), 6.0(2)A8(9), 6.0(2)A8(1), 6.0(2)A8(10a), 7.0(3)I5(1), 9.3(1z), 9.2(2), 7.0(3)F3(4), 7.0(3)I4(8b), 6.0(2)A8(3), 7.0(3)I4(6t), 7.0(3)I5(3a), 6.0(2)A8(8), 7.0(3)I7(5), 7.0(3)F3(3a), 6.0(2)A8(4), 7.0(3)I4(8a), 7.0(3)F3(2), 7.0(3)I4(4), 7.0(3)I7(1), 7.0(3)IA7(2), 7.0(3)IA7(1), 6.0(2)A8(7b), 6.0(2)A8(4a), 9.3(3), 7.0(3)I7(8), 9.3(4), 9.3(5), 7.0(3)I7(9), 9.3(6), 10.1(2), 10.1(1), 9.3(5w), 9.3(7), 9.3(7k), 7.0(3)I7(9w), 10.2(1), 9.3(7a), 9.3(8), 7.0(3)I7(10), 10.2(1q), 10.2(2), 9.3(9), 10.1(2t), 10.2(3), 10.2(3t), 9.3(10), 10.2(2a), 10.3(1), 10.2(4), 10.3(2), 9.3(11), 10.3(3), 10.2(5), 9.3(12), 10.2(3v), 10.4(1), 10.3(99w), 10.2(6), 10.3(3w), 10.3(99x), 10.3(3o), 10.3(4), 10.3(3p), 10.3(4a), 10.4(2), 10.3(3q), 9.3(13), 10.3(5), 10.2(7), 10.4(3), 10.3(3x), 10.3(4g), 10.5(1), 10.2(8), 10.3(3r), 10.3(6), 9.3(14), 10.4(4), 10.3(4h), 10.5(2), 10.4(4g)

Timeline

Official Publish: August 27th, 2025
Last Modified: August 27th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Weaknesses (CWE)

CWE-733

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.