CVE-2020-3284

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 2.8%, top 15% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 0

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

A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity98% × 45%
Exploitation3% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
84.8%
KEV
Not listed

Published

November 6, 2020

Last Modified

November 21, 2024

Advisory Details (1)

Auto-updated Jun 8, 2026
No patch confirmed yet.
generic

Cisco IOS XR Software Enhanced Preboot eXecution Environment Unsigned Code Execution Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-pxe-unsign-code-exec-qAa78fD2

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 42× 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. 2026-07-24 14:14 UTCEPSS rescore
  2. 2026-07-23 14:15 UTCEPSS rescore
  3. 2026-07-23 14:15 UTCEPSS rescore
  4. 2026-07-23 01:52 UTCEG score recompute
  5. 2026-07-22 22:39 UTCEG score recompute
  6. 2026-07-22 14:05 UTCEPSS rescore
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  1. 2026-07-09 19:07 UTCEPSS rescore
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  17. 2026-06-25 13:48 UTCEPSS rescore
  18. 2026-06-24 14:03 UTCEPSS rescore
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  20. 2026-06-23 21:31 UTCEPSS rescore
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  22. 2026-06-22 14:23 UTCEPSS rescore
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  24. 2026-06-21 14:54 UTCEPSS rescore
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  26. 2026-06-19 19:24 UTCEPSS rescore
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  28. 2026-06-18 17:50 UTCEPSS rescore
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  32. 2026-06-15 17:46 UTCEPSS rescore
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  36. 2026-06-10 22:16 UTCEPSS rescore
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  44. 2026-06-05 22:45 UTCEPSS rescore
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  50. 2026-06-02 20:11 UTCEPSS rescore
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  52. 2026-06-01 13:50 UTCEPSS rescore
  53. 2026-05-31 22:29 UTCEPSS rescore
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  60. 2026-05-27 13:39 UTCEPSS rescore
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  64. 2026-05-26 07:17 UTCEPSS rescore
  65. 2026-05-26 07:17 UTCEPSS rescore
  66. 2026-05-23 05:36 UTCEG score recompute
  67. 2026-05-23 05:35 UTCGHSA enrichment

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Frequently asked(5)

What is CVE-2020-3284?
CVE-2020-3284 is a critical vulnerability published on November 6, 2020. A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the…
When was CVE-2020-3284 disclosed?
CVE-2020-3284 was first published in the National Vulnerability Database on November 6, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-3284 actively exploited?
CVE-2020-3284 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 84.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-3284?
CVE-2020-3284 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-3284?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-3284, 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.

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