CVE-2026-20293 - Vulnerability Details

- Cisco UCS and UCS-Based Appliances UEFI Shell Secure Boot Bypass Vulnerability

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.

Published: 2026-09-08

Score: 7.1 High

EPSS: n/a

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco Enterprise NFV Infrastructure Software

unknown

Version	Status	Constraints
`4.1.1`	affected	—
`3.9.1`	affected	—
`3.5.2`	affected	—
`3.12.2`	affected	—
`3.6.2`	affected	—
`3.9.2`	affected	—
`3.11.3`	affected	—
`3.11.1`	affected	—
`3.5.1`	affected	—
`3.3.1`	affected	—
`3.10.2`	affected	—
`3.12.1b`	affected	—
`3.4.1`	affected	—
`3.12.1a`	affected	—
`3.6.3`	affected	—
`3.8.1`	affected	—
`3.11.2`	affected	—
`3.12.1`	affected	—
`3.12.3`	affected	—
`3.10.1`	affected	—
`3.6.1`	affected	—
`3.10.3`	affected	—
`3.7.1`	affected	—
`4.1.2`	affected	—
`4.2.1`	affected	—
`4.2.2`	affected	—
`4.4.1`	affected	—
`4.4.2`	affected	—
`4.5.1`	affected	—
`4.4.3`	affected	—
`4.6.1`	affected	—
`4.7.1`	affected	—
`4.6.2-FC2`	affected	—
`4.6.2`	affected	—
`4.8.1`	affected	—
`4.8.2`	affected	—
`4.9.1`	affected	—
`4.6.3`	affected	—
`4.9.2`	affected	—
`4.10.1`	affected	—
`4.9.3`	affected	—
`4.11.1`	affected	—
`4.9.4`	affected	—
`4.12.1`	affected	—
`4.6.4`	affected	—
`4.12.2`	affected	—
`4.13.1`	affected	—
`4.9.5`	affected	—
`4.12.3`	affected	—
`4.14.1`	affected	—
`4.6.3-FC4`	affected	—
`4.9.4-FC3`	affected	—
`4.12.4`	affected	—
`4.15.1`	affected	—
`4.9.6`	affected	—
`4.15.2`	affected	—
`4.12.5`	affected	—
`4.15.3`	affected	—
`4.15.4`	affected	—
`4.12.6`	affected	—
`4.15.5`	affected	—
`4.12.7`	affected	—
`4.12.8`	affected	—
`4.15.6`	affected	—
`4.9.10`	affected	—

Cisco

Cisco Unified Computing System (Managed)

unknown

Version	Status	Constraints
`4.0(1a)`	affected	—
`4.1(1a)`	affected	—
`4.1(1b)`	affected	—
`4.0(4h)`	affected	—
`4.1(1c)`	affected	—
`4.0(4e)`	affected	—
`4.0(4g)`	affected	—
`4.0(2e)`	affected	—
`4.0(4a)`	affected	—
`4.0(2d)`	affected	—
`4.0(1b)`	affected	—
`4.0(4f)`	affected	—
`4.0(4c)`	affected	—
`4.0(1c)`	affected	—
`4.0(4b)`	affected	—
`4.0(2b)`	affected	—
`4.0(4d)`	affected	—
`4.0(2a)`	affected	—
`4.0(1d)`	affected	—
`4.0(4i)`	affected	—
`4.1(1d)`	affected	—
`4.1(2a)`	affected	—
`4.1(1e)`	affected	—
`4.1(2b)`	affected	—
`4.0(4k)`	affected	—
`4.1(3a)`	affected	—
`4.1(3b)`	affected	—
`4.1(2c)`	affected	—
`4.0(4l)`	affected	—
`4.1(4a)`	affected	—
`4.1(3c)`	affected	—
`4.1(3d)`	affected	—
`4.2(1c)`	affected	—
`4.2(1d)`	affected	—
`4.0(4m)`	affected	—
`4.1(3e)`	affected	—
`4.2(1f)`	affected	—
`4.1(3f)`	affected	—
`4.2(1i)`	affected	—
`4.2(1k)`	affected	—
`4.0(4n)`	affected	—
`4.1(3h)`	affected	—
`4.2(1l)`	affected	—
`4.2(1m)`	affected	—
`4.1(3i)`	affected	—
`4.2(2a)`	affected	—
`4.2(1n)`	affected	—
`4.1(3j)`	affected	—
`4.2(2c)`	affected	—
`4.2(2d)`	affected	—
`4.2(3b)`	affected	—
`4.1(3k)`	affected	—
`4.0(4o)`	affected	—
`4.2(2e)`	affected	—
`4.2(3d)`	affected	—
`4.2(3e)`	affected	—
`4.2(3g)`	affected	—
`4.1(3l)`	affected	—
`4.3(2b)`	affected	—
`4.2(3h)`	affected	—
`4.2(3i)`	affected	—
`4.3(2c)`	affected	—
`4.1(3m)`	affected	—
`4.3(2e)`	affected	—
`4.3(3a)`	affected	—
`4.2(3j)`	affected	—
`4.3(3c)`	affected	—
`4.3(4a)`	affected	—
`4.2(3k)`	affected	—
`4.3(4b)`	affected	—
`4.3(4c)`	affected	—
`4.2(3l)`	affected	—
`4.3(4d)`	affected	—
`4.2(3m)`	affected	—
`4.3(2f)`	affected	—
`4.3(5a)`	affected	—
`4.3(4e)`	affected	—
`4.1(3n)`	affected	—
`4.3(4f)`	affected	—
`4.2(3n)`	affected	—
`4.3(5c)`	affected	—
`4.2(3o)`	affected	—
`4.3(5d)`	affected	—
`4.3(6a)`	affected	—
`4.3(6b)`	affected	—
`4.3(5e)`	affected	—
`4.3(6c)`	affected	—
`6.0(1b)`	affected	—
`4.2(3p)`	affected	—
`6.0(1c)`	affected	—
`4.3(6d)`	affected	—
`6.0(1d)`	affected	—
`6.0(1e)`	affected	—
`4.3(6e)`	affected	—
`6.0(1f)`	affected	—
`4.3(6f)`	affected	—
`6.0(2b)`	affected	—
`6.0(1h)`	affected	—
`4.2(3r)`	affected	—
`6.0(2c)`	affected	—
`4.3(6g)`	affected	—

Cisco

Cisco Unified Computing System (Standalone)

unknown

Version	Status	Constraints
`4.0(2g)`	affected	—
`3.1(2i)`	affected	—
`3.1(1d)`	affected	—
`4.0(4i)`	affected	—
`4.1(1c)`	affected	—
`4.0(2c)`	affected	—
`4.0(1e)`	affected	—
`4.0(2h)`	affected	—
`4.0(4h)`	affected	—
`4.0(1h)`	affected	—
`4.0(2l)`	affected	—
`3.1(3g)`	affected	—
`4.0(1.240)`	affected	—
`4.0(2f)`	affected	—
`4.0(1g)`	affected	—
`4.0(2i)`	affected	—
`3.1(3i)`	affected	—
`4.0(4d)`	affected	—
`4.1(1d)`	affected	—
`3.1(3c)`	affected	—
`4.0(4k)`	affected	—
`3.1(2d)`	affected	—
`3.1(3a)`	affected	—
`3.1(3j)`	affected	—
`4.0(2d)`	affected	—
`4.1(1f)`	affected	—
`4.0(4j)`	affected	—
`4.0(2m)`	affected	—
`4.0(2k)`	affected	—
`4.0(1c)`	affected	—
`4.0(4f)`	affected	—
`4.0(4c)`	affected	—
`3.1(3d)`	affected	—
`3.1(2g)`	affected	—
`3.1(2c)`	affected	—
`4.0(1d)`	affected	—
`3.1(2e)`	affected	—
`4.0(1a)`	affected	—
`4.0(1b)`	affected	—
`3.1(3b)`	affected	—
`4.0(4b)`	affected	—
`3.1(2b)`	affected	—
`4.0(4e)`	affected	—
`3.1(3h)`	affected	—
`4.0(4l)`	affected	—
`4.1(1g)`	affected	—
`4.1(2a)`	affected	—
`4.0(2n)`	affected	—
`4.1(1h)`	affected	—
`3.1(3k)`	affected	—
`4.1(2b)`	affected	—
`4.0(2o)`	affected	—
`4.0(4m)`	affected	—
`4.1(2d)`	affected	—
`4.1(3b)`	affected	—
`4.0(2p)`	affected	—
`4.1(2e)`	affected	—
`4.1(2f)`	affected	—
`4.0(4n)`	affected	—
`4.0(2q)`	affected	—
`4.1(3c)`	affected	—
`4.0(2r)`	affected	—
`4.1(3d)`	affected	—
`4.1(2g)`	affected	—
`4.1(2h)`	affected	—
`4.1(3g)`	affected	—
`4.1(3f)`	affected	—
`4.1(2j)`	affected	—
`4.1(2k)`	affected	—
`4.1(3h)`	affected	—
`4.2(2a)`	affected	—
`4.1(3i)`	affected	—
`4.2(2f)`	affected	—
`4.2(2g)`	affected	—
`4.2(3b)`	affected	—
`4.1(3l)`	affected	—
`4.2(3d)`	affected	—
`4.3(1.230097)`	affected	—
`4.2(1e)`	affected	—
`4.2(1b)`	affected	—
`4.2(1j)`	affected	—
`4.2(1i)`	affected	—
`4.2(1f)`	affected	—
`4.2(1a)`	affected	—
`4.2(1c)`	affected	—
`4.2(1g)`	affected	—
`4.3(1.230124)`	affected	—
`4.1(2l)`	affected	—
`4.2(3e)`	affected	—
`4.3(1.230138)`	affected	—
`4.2(3g)`	affected	—
`4.3(2.230207)`	affected	—
`4.2(3h)`	affected	—
`4.2(3i)`	affected	—
`4.3(2.230270)`	affected	—
`4.1(3m)`	affected	—
`4.1(2m)`	affected	—
`4.3(2.240002)`	affected	—
`4.3(3.240022)`	affected	—
`4.2(3j)`	affected	—
`4.1(3n)`	affected	—
`4.3(2.240009)`	affected	—
`4.3(3.240041)`	affected	—
`4.2(3k)`	affected	—
`4.3(3.240043)`	affected	—
`4.3(4.240142)`	affected	—
`4.3(2.240037)`	affected	—
`4.3(2.240053)`	affected	—
`4.3(4.240152)`	affected	—
`4.2(3l)`	affected	—
`4.3(2.240077)`	affected	—
`4.3(4.242028)`	affected	—
`4.3(4.241063)`	affected	—
`4.3(4.242038)`	affected	—
`4.2(3m)`	affected	—
`4.3(2.240090)`	affected	—
`4.3(5.240021)`	affected	—
`4.3(2.240107)`	affected	—
`4.3(4.242066)`	affected	—
`4.2(3n)`	affected	—
`4.3(5.250001)`	affected	—
`4.2(3o)`	affected	—
`4.3(2.250016)`	affected	—
`4.3(2.250021)`	affected	—
`4.3(5.250030)`	affected	—
`4.3(2.250022)`	affected	—
`4.3(6.250039)`	affected	—
`4.3(6.250040)`	affected	—
`4.3(5.250033)`	affected	—
`4.3(6.250044)`	affected	—
`4.3(6.250053)`	affected	—
`4.3(2.250037)`	affected	—
`4.3(2.250045)`	affected	—
`4.3(4.252001)`	affected	—
`4.3(4.252002)`	affected	—
`6.0(1.250127)`	affected	—
`4.2(3p)`	affected	—
`6.0(1.250131)`	affected	—
`4.3(6.250101)`	affected	—
`6.0(1.250174)`	affected	—
`4.3(6.250117)`	affected	—
`4.3(5.250043)`	affected	—
`4.3(5.250045)`	affected	—
`4.3(6.250060)`	affected	—
`6.0(1.250130)`	affected	—
`4.3(4.241014)`	affected	—
`6.0(1.251030)`	affected	—
`4.3(2.250063)`	affected	—
`6.0(1.250192)`	affected	—
`4.3(6.260003)`	affected	—
`6.0(1.250194)`	affected	—
`6.0(1.260001)`	affected	—
`4.3(6.260017)`	affected	—
`4.3(2.260007)`	affected	—
`6.0(2.260044)`	affected	—
`6.0(2.260042)`	affected	—
`4.0(1.260003)`	affected	—
`2.0(2.260062)`	affected	—
`2.0(1.250127)`	affected	—
`2.0(1.250096)`	affected	—
`4.0(1.260004)`	affected	—
`6.0(2.260026)`	affected	—
`6.0(1.251006)`	affected	—
`1.2(0.250011)`	affected	—
`1.1(0.250016)`	affected	—
`1.0(0.240001)`	affected	—
`1.0(0.250003)`	affected	—
`1.2(0.250013)`	affected	—
`1.1(0.250026)`	affected	—
`1.0(1.250002)`	affected	—
`1.1(0.250022)`	affected	—
`1.1(0.250025)`	affected	—
`1.0(1.250032)`	affected	—
`6.0(2.260034)`	affected	—
`6.0(2.260069)`	affected	—
`4.3(6.260033)`	affected	—
`2.0(2.260101)`	affected	—
`4.2(3q)`	affected	—
`4.2(3r)`	affected	—
`1.2(0.260005)`	affected	—

Cisco

Cisco Unified Computing System E-Series Software (UCSE)

unknown

Version	Status	Constraints
`4.11.1`	affected	—
`4.12.1`	affected	—
`4.12.2`	affected	—
`4.15.2`	affected	—
`4.15.3`	affected	—
`4.15.4`	affected	—

No data.

No data available yet.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-uefi-sb-bypass-eb6xC5GW

History

Tue, 08 Sep 2026 16:30:00 +0000

Type	Values Removed	Values Added
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.
Title		Cisco UCS and UCS-Based Appliances UEFI Shell Secure Boot Bypass Vulnerability
Weaknesses		CWE-749
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-uefi-sb-bypass-eb6xC5GW
Metrics		cvssV3_1 `{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}`

Subscriptions

No data.

MITRE

Status: PUBLISHED

Assigner: cisco

Published: 2026-09-08T16:04:40.874Z

Updated: 2026-09-08T16:04:40.874Z

Reserved: 2025-10-08T11:59:15.405Z

Link: CVE-2026-20293

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-09-08T17:17:34.047

Modified: 2026-09-08T17:17:34.047

Link: CVE-2026-20293

Redhat

No data.

OpenCVE Enrichment

No data.

Weaknesses

CWE-749

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

Subscriptions

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