CVE-2020-3351 | Cisco SD-WAN Solution Software Denial of Service Vulnerability

A vulnerability in Cisco SD-WAN Solution Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper validation of fields in Cisco SD-WAN peering messages that are encapsulated in UDP packets. An attacker could exploit this vulnerability by sending crafted UDP messages to the targeted system. A successful exploit could allow the attacker to cause services on the device to fail, resulting in a DoS condition that could impact the targeted device and other devices that depend on it.

Published: 2020-07-16 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-3351 is rated Moderate Risk (59.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.37%). 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-2020-3351

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 0.56% 1.37% +0.81%
2 2025-03-30 0.76% 0.56% -0.20%
3 2025-03-29 — 0.76% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3351

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-2020-3351

Affected software / configurations for CVE-2020-3351

Vendor Product Version Raw CPE
cisco sd-wan_firmware < 17.2.7 cpe:2.3:o:cisco:sd-wan_firmware:*:*:*:*:*:*:*:*
cisco sd-wan_firmware >= 17.2.8, < 18.3.0 cpe:2.3:o:cisco:sd-wan_firmware:*:*:*:*:*:*:*:*
cisco vedge_cloud_router — cpe:2.3:a:cisco:vedge_cloud_router:-:*:*:*:*:*:*:*
cisco vsmart_controller — cpe:2.3:a:cisco:vsmart_controller:-:*:*:*:*:*:*:*

References for CVE-2020-3351

cvelogic Threat Intelligence