EUVD-2026-15435
GHSA-38h5-57rq-7mj8
CVSS Vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Lifecycle Timeline
3Description
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.
Analysis
This vulnerability in Cisco IOS XE Software bootloader affects Catalyst 9200, ESS9300, IE9310/9320, and IE3500/3505 series switches, allowing authenticated local attackers with level-15 privileges or unauthenticated attackers with physical access to execute arbitrary code at boot time and bypass the chain of trust. An attacker can manipulate loaded binaries to circumvent integrity checks during boot, enabling execution of non-Cisco-signed images. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.
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External POC / Exploit Code
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