CVE-2021-1453
A vulnerability in the software image verification functionality of Cisco IOS XE Software for the Cisco Catalyst 9000 Family of switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time.
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
A vulnerability in the software image verification functionality of Cisco IOS XE Software for the Cisco Catalyst 9000 Family of switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time. The vulnerability is due to an improper check in the code function that manages the verification of the digital signatures of system image files during the initial boot process. An attacker could exploit this vulnerability by loading unsigned software on an affected device. A successful exploit could allow the attacker to boot a malicious software image or execute unsigned code and bypass the image verification check part of the secure boot process of an affected device. To exploit this vulnerability, the attacker would need to have unauthenticated physical access to the device or obtain privileged access to the root shell on the device.
- CVSS 3.1
- 6.8 MEDIUMCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.23% probability · 14th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Affected
- cisco/ios xe
- Source
- psirt@cisco.com
EPSS 0.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.