CVE-2017-3883

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.

Published: 2017-10-19 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2017-3883 is rated High Risk (68.9/100): CVSS High severity, with high exploitation likelihood (EPSS 4.45%, 90th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +2.94% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-3883

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.51% 4.45% +2.94%
2 2026-04-21 1.75% 1.51% -0.24%
3 2026-02-13 1.75%

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-3883

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 4.0 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2017-3883

Affected software / configurations for CVE-2017-3883

Vendor Product Version Raw CPE
cisco firepower_extensible_operating_system <= 2.3 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco fxos 2.3 cpe:2.3:o:cisco:fxos:2.3:*:*:*:*:*:*:*
cisco nx-os 5.2 cpe:2.3:o:cisco:nx-os:5.2:*:*:*:*:*:*:*
cisco nx-os 6.2 cpe:2.3:o:cisco:nx-os:6.2:*:*:*:*:*:*:*
cisco nx-os 6.3 cpe:2.3:o:cisco:nx-os:6.3:*:*:*:*:*:*:*
cisco nx-os 7.3 cpe:2.3:o:cisco:nx-os:7.3:*:*:*:*:*:*:*
cisco nx-os 8.1 cpe:2.3:o:cisco:nx-os:8.1:*:*:*:*:*:*:*
cisco nx-os 8.2 cpe:2.3:o:cisco:nx-os:8.2:*:*:*:*:*:*:*
cisco nx-os <= 4.1 cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:*
cisco nx-os <= 6.0 cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:*
cisco nx-os 7.0 cpe:2.3:o:cisco:nx-os:7.0:*:*:*:*:*:*:*
cisco nx-os 7.0\(3\)i3\(1\) cpe:2.3:o:cisco:nx-os:7.0\(3\)i3\(1\):*:*:*:*:*:*:*
cisco nx-os <= 5.2 cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:*
cisco nx-os 7.1\(0.1\) cpe:2.3:o:cisco:nx-os:7.1\(0.1\):*:*:*:*:*:*:*
cisco nx-os 6.1 cpe:2.3:o:cisco:nx-os:6.1:*:*:*:*:*:*:*
cisco nx-os <= 2.2 cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:*
cisco nx-os 2.5 cpe:2.3:o:cisco:nx-os:2.5:*:*:*:*:*:*:*
cisco nx-os 3.0 cpe:2.3:o:cisco:nx-os:3.0:*:*:*:*:*:*:*
cisco nx-os 3.1 cpe:2.3:o:cisco:nx-os:3.1:*:*:*:*:*:*:*
cisco nx-os 3.2 cpe:2.3:o:cisco:nx-os:3.2:*:*:*:*:*:*:*

References for CVE-2017-3883

cvelogic Threat Intelligence