CVE-2022-0547Network attack vector

Authentication bypass via shared deferred-auth result file

Published Mar 18, 2022 · Updated Nov 3, 2025

Authentication bypass in OpenVPN 2.1 through 2.4.11 and 2.5.0 through 2.5.5 allows remote attackers to access a VPN with partial credentials. OpenVPN passes one shared auth_control_file to parallel deferred authentication plug-ins, making their separate asynchronous results untrustworthy. Only servers configured with at least two deferred external authentication plug-ins are exposed; exploitation grants VPN access despite one incorrect credential factor.

CVSS severity9.8
Critical
EPSS probability3.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in OpenVPN 2.1 through 2.4.11 and 2.5.0 through 2.5.5 allows remote attackers to access a VPN with partial credentials. OpenVPN passes one shared auth_control_file to parallel deferred authentication plug-ins, making their separate asynchronous results untrustworthy. Only servers configured with at least two deferred external authentication plug-ins are exposed; exploitation grants VPN access despite one incorrect credential factor.

The record

CVE
CVE-2022-0547
Published
Mar 18, 2022
Updated
Nov 3, 2025
Vendor
OpenVPN Inc.
Product
OpenVPN
Classifications
CWE-305, CWE-287, T1133
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=version 2.1 until version 2.4.12 and 2.5.6.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenVPN Inc. · OpenVPNversion=version 2.1 until version 2.4.12 and 2.5.6.

Published CVSS scores

9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:P/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-305Authentication Bypass by Primary Weakness
CWE-287Improper Authentication
T1133External Remote Services

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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