CVE-2026-20104

MEDIUM EPSS 5.8%
Published Mar 25, 20263mo ago · Modified Jun 17, 20261w ago
6.1 CVSS 3.1
Medium
Find Similar
Published Mar 25, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

Description

A vulnerability in the bootloader of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches, Cisco Catalyst ESS9300 Embedded Series Switches, Cisco Catalyst IE9310 and IE9320 Rugged Series Switches, and Cisco IE3500 and IE3505 Rugged Series Switches could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to an affected device to execute arbitrary code at boot time and break the chain of trust. This vulnerability is due to insufficient validation of software at boot time. An attacker could exploit this vulnerability by manipulating the loaded binaries on an affected device to bypass some of the integrity checks that are performed during the boot process. A successful exploit could allow the attacker to execute code that bypasses the requirement to run Cisco-signed images. Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates because this vulnerability allows an attacker to bypass a major security feature of a device.

CVSS Details

Base Score
6.1
Exploitability
0.9
Impact
5.2
Vector string
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector Physical
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
5.8% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-124

References 1

  • sec.cloudapps.cisco.com https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xe-secureboot-bypass-B6uYxYSZ

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.