HighAdvisoryCisco PSIRT — security advisories· 25 Mar 2026

Cisco IOS XE Software for Cisco Catalyst and Rugged Series Switches Secure Boot Bypass Vulnerability

Severity: High · Kind: Advisory

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From the source

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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xe-secureboot-bypass-B6uYxYSZ This advisory is part of the March 2026 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a comp

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Plain-English summaries are AI-generated and reviewed for tone, not technical accuracy. For incident response, always rely on the original source linked above.