CVE-2020-3220Network attack vector

VPN session disconnection via unauthenticated ESP tampering

Published Jun 3, 2020 · Updated Nov 15, 2024

Denial of service in Cisco IOS XE Software allows remote attackers to disconnect IPsec VPN sessions through tampered ESP packets. The hardware crypto driver insufficiently verifies the authenticity of received ESP packets before processing attacker-modified cleartext values. Exploitation requires a man-in-the-middle position and an IPsec VPN configuration; it interrupts legitimate sessions without reported data disclosure or modification.

CVSS severity6.8
Medium
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco IOS XE Software allows remote attackers to disconnect IPsec VPN sessions through tampered ESP packets. The hardware crypto driver insufficiently verifies the authenticity of received ESP packets before processing attacker-modified cleartext values. Exploitation requires a man-in-the-middle position and an IPsec VPN configuration; it interrupts legitimate sessions without reported data disclosure or modification.

The record

CVE
CVE-2020-3220
Published
Jun 3, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-345, T1565.002
Attack vector
network
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 vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOS XE Softwareversion=n/a

Published CVSS scores

6.8NISTCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
6.8CiscoCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
T1565.002Transmitted Data Manipulation

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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