CVE-2020-3517 | Cisco FXOS and NX-OS Software Cisco Fabric Services Denial of Service Vulnerability

A vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated attacker to cause process crashes, which could result in a denial of service (DoS) condition on an affected device. The attack vector is configuration dependent and could be remote or adjacent. For more information about the attack vector, see the Details section of this advisory. The vulnerability is due to insufficient error handling when the affected software parses Cisco Fabric Services messages. An attacker could exploit this vulnerability by sending malicious Cisco Fabric Services messages to an affected device. A successful exploit could allow the attacker to cause a reload of an affected device, which could result in a DoS condition.

Published: 2020-08-27 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-3517 is rated Moderate Risk (62.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.51%). Review affected assets and schedule 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-2020-3517

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 2025-11-21 1.32% 1.51% +0.19%
2 2025-11-18 1.51% 1.32% -0.19%
3 2025-03-30 — 1.51% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3517

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/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]
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]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C 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:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2020-3517

Affected software / configurations for CVE-2020-3517

Vendor Product Version Raw CPE
cisco firepower_extensible_operating_system >= 1.1, < 1.1.4.179 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco firepower_extensible_operating_system >= 2.0, < 2.0.1.153 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco firepower_extensible_operating_system >= 2.1, < 2.1.1.86 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco firepower_extensible_operating_system >= 2.2, < 2.2.1.70 cpe:2.3:o:cisco:firepower_extensible_operating_system:*:*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a3\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a3\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a3\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a3\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a3\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a3\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a4\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a4\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a4\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a4\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a4\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a4\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a4\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a4\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a4\(5\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a4\(5\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a4\(6\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a4\(6\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(1a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(1a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(2a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(2a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(3a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(3a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(4a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(4a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(5\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(5\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(5a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(5a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(5b\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(5b\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(6\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(6\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(7\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(7\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a6\(8\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a6\(8\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a7\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a7\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a7\(1a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a7\(1a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a7\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a7\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a7\(2a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a7\(2a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8 cpe:2.3:o:cisco:nx-os:6.0\(2\)a8:*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(4a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(4a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(5\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(5\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(6\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(6\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(6.213\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(6.213\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(7\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(7\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(7a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(7a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(7b\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(7b\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(8\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(8\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(9\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(9\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(9.7\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(9.7\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(10\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(10\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(10a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(10a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(11\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(11\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(11a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(11a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)a8\(11b\) cpe:2.3:o:cisco:nx-os:6.0\(2\)a8\(11b\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u2\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u2\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u2\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u2\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u2\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u2\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u2\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u2\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u2\(5\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u2\(5\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u2\(6\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u2\(6\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(5\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(5\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(6\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(6\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(7\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(7\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(8\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(8\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u3\(9\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u3\(9\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u4\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u4\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u4\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u4\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u4\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u4\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u4\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u4\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u5\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u5\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u5\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u5\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u5\(3\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u5\(3\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u5\(4\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u5\(4\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u6 cpe:2.3:o:cisco:nx-os:6.0\(2\)u6:*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u6\(0.46\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u6\(0.46\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u6\(1\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u6\(1\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u6\(1a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u6\(1a\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u6\(2\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u6\(2\):*:*:*:*:*:*:*
cisco nx-os 6.0\(2\)u6\(2a\) cpe:2.3:o:cisco:nx-os:6.0\(2\)u6\(2a\):*:*:*:*:*:*:*

References for CVE-2020-3517

cvelogic Threat Intelligence