CVE-2026-20293
What it is
A vulnerability in the Unified Extensible Firmware Interface (UEFI) Shell implementation of Cisco UCS Servers and UCS-based appliances could allow an authenticated attacker with valid credentials for a user account with the role of user or admin or an unauthenticated attacker with physical access to an affected device to bypass UEFI Secure Boot validation checks and execute unauthorized software. This vulnerability is due to the availability of memory write commands in the UEFI Shell while UEFI Secure Boot is enabled on a device. An attacker could exploit this vulnerability by selecting the UEFI Shell boot option at boot time and using available shell commands to modify UEFI memory variables. A successful exploit could allow the attacker to manipulate the preboot environment, overwrite UEFI Secure Boot-related memory values, and execute unauthorized software on the affected device.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-749
- Record status
- Analyzed
Affected
- Cisco Enterprise Nfv Infrastructure Software 3.3.1
- Cisco Enterprise Nfv Infrastructure Software 3.4.1
- Cisco Enterprise Nfv Infrastructure Software 3.5.1
- Cisco Enterprise Nfv Infrastructure Software 3.5.2
- Cisco Enterprise Nfv Infrastructure Software 3.6.1
- Cisco Enterprise Nfv Infrastructure Software 3.6.2
- Cisco Enterprise Nfv Infrastructure Software 3.6.3
- Cisco Enterprise Nfv Infrastructure Software 3.7.1
Attack profile CVSS 3.1 · 7.1
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N