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Vulnerabilities/CVE-2026-20293Public Intelligence Dossier
Source: cisco · Limited verification•Last verified: •Collection Degraded
CVE-2026-20293Unknown / EvaluatingHIGH (raw)CVSS 7.1CWE-749

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

Published: 08 Sept 2026•Last updated: 27 Oct 2026, 01:52 AM IST•Source identifier: psirt@cisco.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
7.1HIGH (raw)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Metric sourcepsirt@cisco.com
EPSS probability
0.2%0.002
Percentile8th
Weakness type
CWE-749
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

High

Actively exploited (source statement)

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; Source severity; no confirmed exploitation signal

Affected Products & Remediation

2 source-backed products
Affected products and versions (source)
  • cisco enterprise nfv infrastructure software · 3.3.1; 3.4.1; 3.5.1; 3.5.2; 3.6.1; 3.6.2; 3.6.3; 3.7.1; 3.8.1; 3.9.1; 3.9.2; 3.10.1; 3.10.2; 3.10.3; 3.11.1; 3.11.2; 3.11.3; 3.12.1; 3.12.1a; 3.12.1b; 3.12.2; 3.12.3; 4.1.1; 4.1.2; 4.2.1; 4.2.2; 4.4.1; 4.4.2; 4.4.3; 4.5.1; 4.6.1; 4.6.2; 4.6.2-fc2; 4.6.3; 4.6.3-fc4; 4.6.4; 4.7.1; 4.8.1; 4.8.2; 4.9.1 · NVD CPE · Source
  • cisco unified computing system · version range not provided by source · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched local-access-review (CVSS AV:L, CVSS PR:L)

Exposure

  1. Identify hosts reporting this CVE, prioritising shared or multi-user systems.Telemetry: DeviceTvmSoftwareVulnerabilities · A local, low-privilege vector matters most where untrusted users can run code. · Rule local-access-review

Exploitation evidence

  1. Review source-stated impact and relevant application errors on affected hosts; local access alone does not establish privilege escalation.Telemetry: DeviceProcessEvents · The vector establishes local access and low privileges only. Confirm the impact from the advisory before choosing a specific hunt. · Rule local-access-review

Response

  1. Confirm the source-stated update on affected hosts.Telemetry: DeviceTvmSoftwareVulnerabilities · Host inventory can verify remediation. · Rule local-access-review

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
psirt@cisco.com
Record status · verification
UPDATED · NVD API
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:*:*:*:*:*:*:*

Evidence & Provenance

2 public sources
sec.cloudapps.cisco.comSource recordnvd.nist.govSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-20293
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-20293
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-20293"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.