CVE-2026-20293

highpriority · track · 28EPSS 0.002 · 8 %ileDEUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.18% (8th) EPSS
CVSS 7.1 · high
Is it mine?
615 products
Check your exposure
Who says so?
2 sources
cert_bund · cisco_csaf

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–7.1

v3.17.1highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Nprimary · psirt@cisco.com USexploitability 1.8 · impact 5.2
v3.16.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:Usecondary · CVSS-BT (t0sche)
v3.17.1highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-749US
05

affected products (615)

Products and version ranges known to be affected.

showing 20 of 615
06

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-3240Insyde UEFI Firmware und Cisco UCS (UEFI Shell Secure Boot): Schwachstelle ermöglicht Umgehen von SicherheitsvorkehrungenDeutsch2026-09-08csaf · cert_bundDE

    Ein Angreifer kann eine Schwachstelle in Insyde UEFI Firmware und Cisco Unified Computing System (UCS) ausnutzen, um den UEFI-Secure-Boot zu umgehen, die Pre-Boot-Umgebung zu manipulieren und beliebigen Code auszuführen.

  • cisco-sa-ucs-uefi-sb-bypass-eb6xC5GWCisco UCS and UCS-Based Appliances UEFI Shell Secure Boot Bypass Vulnerability2026-09-08csaf · cisco_csafUS

    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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

07

sources

Which sources assert this record, and when.

cert_bundcisco_csafNVDCVE.orgMITRE
published 2026-09-08modified 2026-10-26
08

references (1) nvd

External citations — patches, advisories, analysis.

scry

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