Threat intelligence dashboard
CVE-2026-20293high

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

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.

Risk score

7.1

CVSS 3.1

Vendor
Cisco
Product
Cisco Enterprise NFV Infrastructure Software, Cisco Unified Computing System (Managed), Cisco Unified Computing System (Standalone), Cisco Unified Computing System E-Series Software (UCSE)
CWE
CWE-749
Published
Sep 8, 2026
Updated
Sep 16, 2026
CISA KEV
Not flagged

Affected products and versions

Cisco Enterprise NFV Infrastructure Software

Cisco

Version / rangeStatusType
4.1.1affected—
3.9.1affected—
3.5.2affected—
3.12.2affected—
3.6.2affected—
3.9.2affected—
3.11.3affected—
3.11.1affected—
3.5.1affected—
3.3.1affected—
3.10.2affected—
3.12.1baffected—
3.4.1affected—
3.12.1aaffected—
3.6.3affected—
3.8.1affected—
3.11.2affected—
3.12.1affected—
3.12.3affected—
3.10.1affected—
3.6.1affected—
3.10.3affected—
3.7.1affected—
4.1.2affected—
4.2.1affected—
4.2.2affected—
4.4.1affected—
4.4.2affected—
4.5.1affected—
4.4.3affected—
4.6.1affected—
4.7.1affected—
4.6.2-FC2affected—
4.6.2affected—
4.8.1affected—
4.8.2affected—
4.9.1affected—
4.6.3affected—
4.9.2affected—
4.10.1affected—
4.9.3affected—
4.11.1affected—
4.9.4affected—
4.12.1affected—
4.6.4affected—
4.12.2affected—
4.13.1affected—
4.9.5affected—
4.12.3affected—
4.14.1affected—
4.6.3-FC4affected—
4.9.4-FC3affected—
4.12.4affected—
4.15.1affected—
4.9.6affected—
4.15.2affected—
4.12.5affected—
4.15.3affected—
4.15.4affected—
4.12.6affected—
4.15.5affected—
4.12.7affected—
4.12.8affected—
4.15.6affected—
4.9.10affected—

Cisco Unified Computing System (Managed)

Cisco

Version / rangeStatusType
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 Unified Computing System (Standalone)

Cisco

Version / rangeStatusType
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 Unified Computing System E-Series Software (UCSE)

Cisco

Version / rangeStatusType
4.11.1affected—
4.12.1affected—
4.12.2affected—
4.15.2affected—
4.15.3affected—
4.15.4affected—

Technical metrics

7.1

CVSS 3.1

Severity
high
Source
cisco
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N