CVE-2016-6420

Cisco FireSIGHT System Software 4.10.3 through 5.4.0 in Firepower Management Center allows remote authenticated users to bypass authorization checks and gain privileges via a crafted HTTP request, aka Bug ID CSCur25467.

Published: 2016-10-05 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-6420 is rated Moderate Risk (54.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.84%). EPSS rose +1.79% over the last day, indicating growing attacker interest. 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-2016-6420

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 0.05% 1.84% +1.79%
2 2025-03-30 0.10% 0.05% -0.05%
3 2025-03-29 — 0.10% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-6420

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N 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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:L/Au:S/C:C/I:N/A:N 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:C)
Complete confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 6.9 [email protected]

Weakness enumeration for CVE-2016-6420

Affected software / configurations for CVE-2016-6420

Vendor Product Version Raw CPE
cisco firesight_system_software 4.10.3 cpe:2.3:a:cisco:firesight_system_software:4.10.3:*:*:*:*:*:*:*
cisco firesight_system_software 5.2.0 cpe:2.3:a:cisco:firesight_system_software:5.2.0:*:*:*:*:*:*:*
cisco firesight_system_software 5.3.0 cpe:2.3:a:cisco:firesight_system_software:5.3.0:*:*:*:*:*:*:*
cisco firesight_system_software 5.3.1 cpe:2.3:a:cisco:firesight_system_software:5.3.1:*:*:*:*:*:*:*
cisco firesight_system_software 5.4.0 cpe:2.3:a:cisco:firesight_system_software:5.4.0:*:*:*:*:*:*:*

References for CVE-2016-6420

cvelogic Threat Intelligence