← Vulnerability feed

Vulnerability record · CVE-2017-3883 · published 19 October 2017

CVE-2017-3883: Cisco firepower extensible operating system allocation without limits vulnerability

Cisco · Firepower Extensible Operating System

A vulnerability in the authentication, authorization, and accounting (AAA) implementation of Cisco Firepower Extensible Operating System (FXOS) and NX-OS System Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability occurs because AAA processes prevent the NX-OS System Manager from receiving keepalive messages when an affected device receives a high rate of login attempts, such as in a brute-force login attack. System memory can run low on the FXOS devices under the same conditions, which could cause the AAA process to unexpectedly restart or cause the device to reload. An attacker could exploit this vulnerability by performing a brute-force login attack against a device that is configured with AAA security services. A successful exploit could allow the attacker to cause the affected device to reload. This vulnerability affects the following Cisco products if they are running Cisco FXOS or NX-OS System Software that is configured for AAA services: Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System (UCS) 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCuq58760, CSCuq71257, CSCur97432, CSCus05214, CSCux54898, CSCvc33141, CSCvd36971, CSCve03660.

8.6 CVSS 3.0 High EPSS 4.5% · top 8.9% CWE-770 · Allocation without limits
8.6CVSS 3.0 base score, v2 5.0
4.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

A vulnerability in the authentication, authorization, and accounting (AAA) implementation of Cisco Firepower Extensible Operating System (FXOS) and NX-OS System Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability occurs because AAA processes prevent the NX-OS System Manager from receiving keepalive messages when an affected device receives a high rate of login attempts, such as in a brute-force login attack. System memory can run low on the FXOS devices under the same conditions, which could cause the AAA process to unexpectedly restart or cause the device to reload. An attacker could exploit this vulnerability by performing a brute-force login attack against a device that is configured with AAA security services. A successful exploit could allow the attacker to cause the affected device to reload. This vulnerability affects the following Cisco products if they are running Cisco FXOS or NX-OS System Software that is configured for AAA services: Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System (UCS) 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCuq58760, CSCuq71257, CSCur97432, CSCus05214, CSCux54898, CSCvc33141, CSCvd36971, CSCve03660.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

Track CVE-2017-3883 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2021-44228Apache Log4j2 JNDI lookup remote code executionApache Log4j2 versions 2.0-beta9 through 2.15.0 (excluding 2.12.2, 2.12.3, and 2.3.1) do not protect against attacker-controlled LDAP and other JNDI …KEVEPSS 100%analysed6.7CVE-2024-20399Cisco NX-OS CLI command injection allows root command executionCisco NX-OS fails to properly validate arguments passed to specific configuration CLI commands, allowing OS command injection. An attacker who alread…KEVEPSS 4.3%analysed9.8CVE-2018-0310Cisco nx-os out-of-bounds read vulnerabilityA vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, remote attacke…EPSS 4.1%9.8CVE-2018-0301Cisco nx-os improper input validation vulnerabilityA vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to craft a packet to the management int…EPSS 17%9.8CVE-2016-1453Cisco nx-os memory buffer overflow vulnerabilityBuffer overflow in the Overlay Transport Virtualization (OTV) GRE feature in Cisco NX-OS 5.0 through 7.3 on Nexus 7000 and 7700 devices allows remote…EPSS 8.1%9.8CVE-2016-1341Cisco nx-os permissions and access controls vulnerabilityCisco NX-OS 7.0(1)N1(1), 7.0(1)N1(3), and 7.0(4)N1(1) on Nexus 2000 Fabric Extender devices has a blank root password, which allows local users to ga…EPSS 1.1%9.8CVE-2015-6435Cisco firepower extensible operating system os command injection vulnerabilityAn unspecified CGI script in Cisco FX-OS before 1.1.2 on Firepower 9000 devices and Cisco Unified Computing System (UCS) Manager before 2.2(4b), 2.2(…EPSS 8.7%9.1CVE-2021-1361Cisco nx-os vulnerabilityA vulnerability in the implementation of an internal file management service for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switche…EPSS 1.6%

Source: NIST National Vulnerability Database (record CVE-2017-3883), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.