CVE-2019-1599: A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condit...

Description

A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. The vulnerability is due to an issue with allocating and freeing memory buffers in the network stack. An attacker could exploit this vulnerability by sending crafted TCP streams to an affected device in a sustained way. A successful exploit could cause the network stack of an affected device to run out of available buffers, impairing operations of control plane and management plane protocols, resulting in a DoS condition. Note: This vulnerability can be triggered only by traffic that is destined to an affected device and cannot be exploited using traffic that transits an affected device. Nexus 1000V Switch for Microsoft Hyper-V is affected in versions prior to 5.2(1)SM3(2.1). Nexus 1000V Switch for VMware vSphere is affected in versions prior to 5.2(1)SV3(4.1a). Nexus 3000 Series Switches are affected in versions prior to 7.0(3)I7(6) and 9.2(2). Nexus 3500 Platform Switches are affected in versions prior to 6.0(2)A8(11), 7.0(3)I7(6), and 9.2(2). Nexus 3600 Platform Switches are affected in versions prior to 7.0(3)F3(5) and 9.2(2). Nexus 5500, 5600, and 6000 Series Switches are affected in versions prior to 7.1(5)N1(1b) and 7.3(5)N1(1). Nexus 7000 and 7700 Series Switches are affected in versions prior to 6.2(22. Nexus 9500 R-Series Line Cards and Fabric Modules are affected in versions prior to 7.0(3)F3(5) and 9.2(2). UCS 6200 and 6300 Series Fabric Interconnect are affected in versions prior to 3.2(3j) and 4.0(2a). UCS 6400 Series Fabric Interconnect are affected in versions prior to 4.0(2a).

Metrics

CVSS 3.1

8.6/10

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

EPSS Probability

14.17%

96.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Nx-Os	>= 9.2, < 9.2\(2\)
Cisco	Nx-Os	>= 7.0\(3\), < 7.0\(3\)i7\(5\)
Cisco	Nx-Os	>= 7.0\(3\), < 7.0\(3\)f3\(5\)
Cisco	Nx-Os	>= 7.2, < 7.3\(5\)n1\(1\)
Cisco	Nx-Os	>= 8.3, < 8.3\(2\)
Cisco	Nx-Os	< 6.0\(2\)a8\(11\)
Cisco	Nx-Os	< 6.2\(22\)
Cisco	Nx-Os	>= 7.0\(3\)i5, < 7.0\(3\)i7\(6\)
Cisco	Nx-Os	< 5.2\(1\)sm3\(2.1\)
Cisco	Nx-Os	< 5.2\(1\)sv3\(4.1a\)
Cisco	Nx-Os	>= 4.0, < 4.0\(2a\)
Cisco	Nx-Os	< 3.2\(3j\)
Cisco	Nx-Os	< 7.0\(3\)i4\(9\)
Cisco	Nx-Os	< 7.1\(5\)n1\(1b\)
Cisco	Nx-Os	>= 8.0, < 8.2\(3\)
Cisco	Nx-Os	>= 7.2, < 7.3\(3\)d1\(1\)

References

http://www.securityfocus.com/bid/107342Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190306-nxos-netstackPatch, Vendor Advisory
http://www.securityfocus.com/bid/107342Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190306-nxos-netstackPatch, Vendor Advisory

Timeline

Published: Mar 7, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-1599?

A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. The vulnerability is due to an issue with allocating and freeing memory buffers in the network stack. An attacker could exploit this vulnerability by sending crafted TCP streams to an affected device in a sustained way. A successful exploit could cause the network stack of an affected device to run out of available buffers, impairing operations of control plane and management plane protocols, resulting in a DoS condition. Note: This vulnerability can be triggered only by traffic that is destined to an affected device and cannot be exploited using traffic that transits an affected device. Nexus 1000V Switch for Microsoft Hyper-V is affected in versions prior to 5.2(1)SM3(2.1). Nexus 1000V Switch for VMware vSphere is affected in versions prior to 5.2(1)SV3(4.1a). Nexus 3000 Series Switches are affected in versions prior to 7.0(3)I7(6) and 9.2(2). Nexus 3500 Platform Switches are affected in versions prior to 6.0(2)A8(11), 7.0(3)I7(6), and 9.2(2). Nexus 3600 Platform Switches are affected in versions prior to 7.0(3)F3(5) and 9.2(2). Nexus 5500, 5600, and 6000 Series Switches are affected in versions prior to 7.1(5)N1(1b) and 7.3(5)N1(1). Nexus 7000 and 7700 Series Switches are affected in versions prior to 6.2(22. Nexus 9500 R-Series Line Cards and Fabric Modules are affected in versions prior to 7.0(3)F3(5) and 9.2(2). UCS 6200 and 6300 Series Fabric Interconnect are affected in versions prior to 3.2(3j) and 4.0(2a). UCS 6400 Series Fabric Interconnect are affected in versions prior to 4.0(2a).

How severe is CVE-2019-1599?

CVE-2019-1599 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 14.17% probability of exploitation in the next 30 days.

How do I fix CVE-2019-1599?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.