CVE-2020-3455

Cisco FXOS Software for Firepower 4100/9300 Series Appliances Secure Boot Bypass Vulnerability

HIGH

7.8

CVSS Score

Published: October 21, 2020 at 06:36 PM UTC

Updated: June 17, 2026 at 03:18 AM UTC

17 products affected across 1 vendorFirepower Extensible Operating SystemFirepower 4110Firepower 4140

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Severity

HIGH7.8

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

A vulnerability in the secure boot process of Cisco FXOS Software could allow an authenticated, local attacker to bypass the secure boot mechanisms. The vulnerability is due to insufficient protections of the secure boot process. An attacker could exploit this vulnerability by injecting code into a specific file that is then referenced during the device boot process. A successful exploit could allow the attacker to break the chain of trust and inject code into the boot process of the device which would be executed at each boot and maintain persistence across reboots.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Firepower Extensible Operating System · Cisco

95%

v < 2.4.1.2682.6 ≤ v < 2.6.1.2142.7 ≤ v < 2.7.1.131

Affected range stops below 2.4.1.268, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.6.1.214, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.7.1.131, so it looks safe — our inference, not a vendor statement

cisco-firepower-4110 (environment) · cisco-firepower-4112 (environment) · cisco-firepower-4115 (environment) · cisco-firepower-4120 (environment) · cisco-firepower-4125 (environment) · cisco-firepower-4140 (environment) · cisco-firepower-4145 (environment) · cisco-firepower-4150 (environment) · cisco-firepower-9300-sm-24 (environment) · cisco-firepower-9300-sm-36 (environment) · cisco-firepower-9300-sm-40 (environment) · cisco-firepower-9300-sm-44 (environment) · cisco-firepower-9300-sm-44-x-3 (environment) · cisco-firepower-9300-sm-48 (environment) · cisco-firepower-9300-sm-56 (environment) · cisco-firepower-9300-sm-56-x-3 (environment)

Firepower 4110 · Ciscodevice

80%

All versions

Firepower 4112 · Ciscodevice

80%

All versions

Firepower 4115 · Ciscodevice

80%

All versions

Firepower 4120 · Ciscodevice

80%

All versions