CVE-2026-20293: Exposed Dangerous Method or Function in Cisco Cisco Enterprise NFV Infrastructure Software
Description
CVE-2026-20293 is a high-severity vulnerability in the UEFI Shell implementation of Cisco UCS Servers and UCS-based appliances. It allows an authenticated user with user or admin roles, or an unauthenticated attacker with physical access, to bypass UEFI Secure Boot validation by exploiting memory write commands available in the UEFI Shell. This enables unauthorized software execution by manipulating UEFI memory variables during boot. The vulnerability affects multiple specific versions of Cisco Enterprise NFV Infrastructure Software.
CVSS v3.1
7.1high
Affected software
Cisco
Cisco Enterprise NFV Infrastructure Software
Cisco
Cisco Unified Computing System (Managed)
Cisco
Cisco Unified Computing System (Standalone)
Cisco
Cisco Unified Computing System E-Series Software (UCSE)
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability arises from the availability of memory write commands in the UEFI Shell while UEFI Secure Boot is enabled on affected Cisco UCS Servers and UCS-based appliances. An attacker can select the UEFI Shell boot option and use shell commands to modify UEFI memory variables related to Secure Boot. Successful exploitation allows bypassing Secure Boot validation and executing unauthorized software in the preboot environment. The vulnerability affects numerous specific versions of Cisco Enterprise NFV Infrastructure Software as listed.
Potential Impact
Exploitation could allow an attacker with valid credentials or physical access to bypass UEFI Secure Boot protections, leading to unauthorized software execution in the preboot environment. This compromises system integrity and could facilitate persistent, low-level attacks. The CVSS v3.1 score is 7.1 (high), reflecting the significant confidentiality and integrity impact without availability impact.
Mitigation Recommendations
No patch or official fix information is provided in the available data. Patch status is not yet confirmed — check the Cisco vendor advisory for current remediation guidance. Until a fix is available, restrict physical access to affected devices and limit user roles to trusted personnel to reduce risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 10/08/2025
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aa03a23acd9273b49ec35ec
Added to database: 09/08/2026, 16:38:59 UTC
Last enriched: 09/23/2026, 06:14:23 UTC
Last updated: 10/24/2026, 08:45:10 UTC
Views: 98
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