CVE-2026-20293
Cisco UCS and UCS-Based Appliances UEFI Shell Secure Boot Bypass Vulnerability
HIGH 7.1
At a glance
- Source
- NVD
- EPSS
- EPSS 0.18 % · percentile 8 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- cisco
- NVD status
- Analyzed
Description
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.
Weaknesses (CWE)
- CWE-749 — Exposed Dangerous Method or Function
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | cisco |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | NVD · psirt@cisco.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-72936
- GCVE · GCVE-0-2026-20293
CERT-FR advisories
- CERTFR-2026-AVI-1138 — Vulnérabilité dans les produits Cisco · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.3.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.4.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.5.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.5.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.6.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.6.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.6.3:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.7.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.8.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.9.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.9.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.10.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.10.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.10.3:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.11.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.11.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.11.3:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.12.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.12.1a:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.12.1b:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.12.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:3.12.3:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.1.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.1.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.2.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.2.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.4.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.4.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.4.3:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.5.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.6.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.6.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.6.2-fc2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.6.3:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.6.3-fc4:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.6.4:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.7.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.8.1:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.8.2:*:*:*:*:*:*:*cpe:2.3:a:cisco:enterprise_nfv_infrastructure_software:4.9.1:*:*:*:*:*:*:*- +311 more
Affected products
| Product | Versions |
|---|---|
| Cisco · Cisco Enterprise NFV Infrastructure Software | affected 4.1.1 ; affected 3.9.1 ; affected 3.5.2 ; affected 3.12.2 ; affected 3.6.2 ; affected 3.9.2 |
| Cisco · Cisco Unified Computing System (Managed) | affected 4.0(1a) ; affected 4.1(1a) ; affected 4.1(1b) ; affected 4.0(4h) ; affected 4.1(1c) ; affected 4.0(4e) |
| Cisco · Cisco Unified Computing System (Standalone) | affected 4.0(2g) ; affected 3.1(2i) ; affected 3.1(1d) ; affected 4.0(4i) ; affected 4.1(1c) ; affected 4.0(2c) |
| Cisco · Cisco Unified Computing System E-Series Software (UCSE) | affected 4.11.1 ; affected 4.12.1 ; affected 4.12.2 ; affected 4.15.2 ; affected 4.15.3 ; affected 4.15.4 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |