CVE-2020-3208

Malicious image boot via verification bypass

Published Jun 3, 2020 · Updated Nov 15, 2024

Image verification bypass in Cisco IOS on 809 and 829 Industrial ISRs allows local users to boot a malicious software image. The VDS shell applies insufficient access restrictions to image-verification controls, allowing integrity verification to be disabled. Exploitation requires local VDS access with valid privilege level 15 credentials and permits an attacker-controlled IOS image to run at boot.

CVSS severity6.7
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Image verification bypass in Cisco IOS on 809 and 829 Industrial ISRs allows local users to boot a malicious software image. The VDS shell applies insufficient access restrictions to image-verification controls, allowing integrity verification to be disabled. Exploitation requires local VDS access with valid privilege level 15 credentials and permits an attacker-controlled IOS image to run at boot.

The record

CVE
CVE-2020-3208
Published
Jun 3, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco IOS
Classifications
CWE-264, T1601
Attack vector
local
Privileges
admin

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 vectorlocal
Required privilegesadmin

What is affected?

ClamAV · Cisco IOSversion=n/a

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
6.7Cisco Systems, Inc.CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-264Permissions, Privileges, and Access Controls
T1601Modify System Image

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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