CVE-2020-20813Network attack vector

Service interruption via crafted control-channel reset packet

Published Aug 22, 2023 · Updated Oct 4, 2024

Denial of service in OpenVPN 2.4.7 and earlier allows remote attackers to interrupt the VPN daemon via a crafted control-channel reset packet. OpenVPN has not published the specific control-channel operation that mishandles the packet, and Ubuntu reports that upstream did not issue or manage this CVE. No authentication or user interaction is required, and the documented consequence is limited to loss of service availability.

CVSS severity7.5
High
EPSS probability0.92%
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 OpenVPN 2.4.7 and earlier allows remote attackers to interrupt the VPN daemon via a crafted control-channel reset packet. OpenVPN has not published the specific control-channel operation that mishandles the packet, and Ubuntu reports that upstream did not issue or manage this CVE. No authentication or user interaction is required, and the documented consequence is limited to loss of service availability.

The record

CVE
CVE-2020-20813
Published
Aug 22, 2023
Updated
Oct 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-404, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3SUSECVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5StormshieldCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.7StormshieldCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

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-404Improper Resource Shutdown or Release
T1499.004Application or System Exploitation

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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