CVE-2020-5136

A buffer overflow vulnerability in SonicOS allows an authenticated attacker to cause Denial of Service (DoS) in the SSL-VPN and virtual assist portal, which leads to a firewall crash. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version 7.0.0.0.

Published: 2020-10-12 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-5136 is rated Moderate Risk (48.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.10%). 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-2020-5136

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 0.33% 1.10% +0.77%
2 2025-03-30 0.39% 0.33% -0.06%
3 2025-03-29 — 0.39% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-5136

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
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.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/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:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2020-5136

Affected software / configurations for CVE-2020-5136

Vendor Product Version Raw CPE
sonicwall sonicos <= 5.9.1.13 cpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos >= 6.0.0.0, <= 6.0.5.3 cpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos >= 6.5.0.0, <= 6.5.1.11 cpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos >= 6.5.4.0, <= 6.5.4.7 cpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos 7.0.0.0 cpe:2.3:o:sonicwall:sonicos:7.0.0.0:*:*:*:*:*:*:*
sonicwall sonicosv <= 6.5.4.4 cpe:2.3:o:sonicwall:sonicosv:*:*:*:*:*:*:*:*

References for CVE-2020-5136

cvelogic Threat Intelligence