CVE-2026-20293

HIGHPre-NVD 7.17.1—
EchelonGraph scoreHIGH confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-09-08. the CNA's CVSS baseline 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:cisco, epss, ghsa
Trending — 3 sources updated this week
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.1
EG Score
7.1(high)
EG Risk
32(Track)
EG Risk 32/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

September 8, 2026

Last Modified

September 16, 2026

Advisory Details (1)

Auto-updated Sep 8, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

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

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

Vendor Advisories for CVE-2026-20293(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 26× in last 7d / 45× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 09:54 UTCGHSA enrichment
  2. 2026-09-18 21:21 UTCEG score recompute
  3. 2026-09-18 21:21 UTCGHSA enrichment
  4. 2026-09-18 19:27 UTCEPSS rescore
  5. 2026-09-18 08:35 UTCGHSA enrichment
  6. 2026-09-17 20:19 UTCEG score recompute
  7. 2026-09-17 20:19 UTCGHSA enrichment
  8. 2026-09-17 06:45 UTCGHSA enrichment
  9. 2026-09-16 18:18 UTCEG score recompute
  10. 2026-09-16 18:17 UTCGHSA enrichment
  11. 2026-09-16 14:07 UTCEPSS rescore
  12. 2026-09-16 05:15 UTCEPSS rescore
  13. 2026-09-16 04:22 UTCEG score recompute
  14. 2026-09-16 04:22 UTCGHSA enrichment
  15. 2026-09-15 16:37 UTCGHSA enrichment
  16. 2026-09-15 04:16 UTCEG score recompute
  17. 2026-09-15 04:16 UTCGHSA enrichment
  18. 2026-09-14 16:00 UTCGHSA enrichment
  19. 2026-09-14 03:44 UTCEG score recompute
  20. 2026-09-14 03:44 UTCGHSA enrichment
  21. 2026-09-13 16:47 UTCEPSS rescore
  22. 2026-09-13 15:28 UTCGHSA enrichment
  23. 2026-09-13 03:12 UTCEG score recompute
  24. 2026-09-13 03:12 UTCGHSA enrichment
  25. 2026-09-12 15:01 UTCEPSS rescore
Show 20 more
  1. 2026-09-12 14:56 UTCGHSA enrichment
  2. 2026-09-12 02:40 UTCGHSA enrichment
  3. 2026-09-11 14:24 UTCEG score recompute
  4. 2026-09-11 14:24 UTCGHSA enrichment
  5. 2026-09-11 13:51 UTCEG score recompute
  6. 2026-09-11 13:51 UTCGHSA enrichment
  7. 2026-09-11 12:06 UTCEG score recompute
  8. 2026-09-11 12:06 UTCGHSA enrichment
  9. 2026-09-11 09:36 UTCEPSS rescore
  10. 2026-09-10 23:50 UTCGHSA enrichment
  11. 2026-09-10 11:24 UTCEG score recompute
  12. 2026-09-10 11:23 UTCGHSA enrichment
  13. 2026-09-10 09:34 UTCEPSS rescore
  14. 2026-09-09 23:06 UTCGHSA enrichment
  15. 2026-09-09 08:05 UTCGHSA enrichment
  16. 2026-09-08 19:49 UTCEG score recompute
  17. 2026-09-08 19:49 UTCGHSA enrichment
  18. 2026-09-08 18:14 UTCEG score recompute
  19. 2026-09-08 16:29 UTCEG score recompute
  20. 2026-09-08 16:25 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-20293?
CVE-2026-20293 is a high vulnerability published on September 8, 2026. 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…
When was CVE-2026-20293 disclosed?
CVE-2026-20293 was first published in the National Vulnerability Database on September 8, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20293 actively exploited?
CVE-2026-20293 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.9% of all scored CVEs.
What is the CVSS score of CVE-2026-20293?
CVE-2026-20293 has a CVSS v4.0 base score of 7.1 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-20293?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20293, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-20293

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