CVE-2020-11810Network attack vector

VPN session interruption via peer-id initialization race

Published Apr 27, 2020 · Updated Aug 4, 2024

Race condition in OpenVPN 2.4.0 through 2.4.8 allows remote attackers to drop another client's VPN connection via a timed P_DATA_V2 packet. A zero-length buffer from tls_pre_decrypt() makes openvpn_decrypt() report success, allowing multi_process_float() to commit the spoofed address. Exploitation requires NCP and precise timing before data-channel key initialization; it interrupts one session without injecting or stealing VPN traffic.

CVSS severity3.7
Low
EPSS probability1.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in OpenVPN 2.4.0 through 2.4.8 allows remote attackers to drop another client's VPN connection via a timed P_DATA_V2 packet. A zero-length buffer from tls_pre_decrypt() makes openvpn_decrypt() report success, allowing multi_process_float() to commit the spoofed address. Exploitation requires NCP and precise timing before data-channel key initialization; it interrupts one session without injecting or stealing VPN traffic.

The record

CVE
CVE-2020-11810
Published
Apr 27, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-362, CAPEC-26, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 27, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

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

3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CAPEC-26Leveraging Race Conditions
T1499.004Application or System Exploitation

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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