CVE-2016-5311

A Privilege Escalation vulnerability exists in Symantec Norton Antivirus, Norton AntiVirus with Backup, Norton Security, Norton Security with Backup, Norton Internet Security, Norton 360, Endpoint Protection Small Business Edition Cloud, and Endpoint Protection Cloud Client due to a DLL-preloading without path restrictions, which could let a local malicious user obtain system privileges.

Published: 2020-01-09 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-5311 is rated Moderate Risk (48.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.71%). 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-2016-5311

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 0.29% 0.71% +0.42%
2 2025-03-17 0.22% 0.29% +0.07%
3 2023-03-07 — 0.22% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-5311

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
6.9 2.0 MEDIUM
AV:L/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 3.4 10.0 [email protected]

Weakness enumeration for CVE-2016-5311

Affected software / configurations for CVE-2016-5311

Vendor Product Version Raw CPE
symantec endpoint_protection < 22.8.0.50 cpe:2.3:a:symantec:endpoint_protection:*:*:*:*:*:*:*:*
symantec endpoint_protection_cloud < 22.8.0.50 cpe:2.3:a:symantec:endpoint_protection_cloud:*:*:*:*:*:*:*:*
symantec norton_360 < 22.7 cpe:2.3:a:symantec:norton_360:*:*:*:*:*:*:*:*
symantec norton_antivirus < 22.7 cpe:2.3:a:symantec:norton_antivirus:*:*:*:*:*:*:*:*
symantec norton_antivirus_with_backup < 22.7 cpe:2.3:a:symantec:norton_antivirus_with_backup:*:*:*:*:*:*:*:*
symantec norton_family < 22.7 cpe:2.3:a:symantec:norton_family:*:*:*:*:*:*:*:*
symantec norton_internet_security < 22.7 cpe:2.3:a:symantec:norton_internet_security:*:*:*:*:*:*:*:*
symantec norton_security < 22.7 cpe:2.3:a:symantec:norton_security:*:*:*:*:*:*:*:*
symantec norton_security_with_backup < 22.7 cpe:2.3:a:symantec:norton_security_with_backup:*:*:*:*:*:*:*:*

References for CVE-2016-5311

cvelogic Threat Intelligence