CVE-2020-3209

Unsigned code execution via boot signature bypass

Published Jun 3, 2020 · Updated Nov 15, 2024

Signature verification bypass in Cisco IOS XE Software allows physically proximate attackers to boot malicious images or run unsigned binaries. The initial boot image-verification path improperly accepts system image files whose digital signatures have not been validly verified. Exploitation requires physical access to load unsigned software and grants control over code executed by the targeted network device.

CVSS severity6.8
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Signature verification bypass in Cisco IOS XE Software allows physically proximate attackers to boot malicious images or run unsigned binaries. The initial boot image-verification path improperly accepts system image files whose digital signatures have not been validly verified. Exploitation requires physical access to load unsigned software and grants control over code executed by the targeted network device.

The record

CVE
CVE-2020-3209
Published
Jun 3, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-347, T1601.001
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOS XE Softwareversion=n/a

Published CVSS scores

6.8Cisco Systems, Inc.CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1601.001Patch System Image

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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