CVE-2022-0547

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-03-18 · updated 2026-06-17
Weakness: CWE-305

Description

OpenVPN 2.1 until v2.4.12 and v2.5.6 may enable authentication bypass in external authentication plug-ins when more than one of them makes use of deferred authentication replies, which allows an external user to be granted access with only partially correct credentials.

Affected products

Debian Linux: 9.0
Fedoraproject Fedora: 34, 36
OpenVPN: from 2.1.0 before 2.4.12; from 2.5.0 before 2.5.6 — fixed in 2.4.12, 2.5.6

How to fix

Upgrade to a fixed version: OpenVPN 2.4.12, 2.5.6. Check the vendor advisory for mitigations.

References

https://community.openvpn.net/openvpn/wiki/CVE-2022-0547
https://community.openvpn.net/openvpn/wiki/SecurityAnnouncements
https://lists.debian.org/debian-lts-announce/2022/05/msg00002.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GFXJ35WKPME4HYNQCQNAJHLCZOJL2SAE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R36OYC5SJ6FLPVAYJYYT4MOJ2I7MGYFF/
https://openvpn.net/community-downloads/
https://community.openvpn.net/openvpn/wiki/CVE-2022-0547
https://community.openvpn.net/openvpn/wiki/SecurityAnnouncements
https://lists.debian.org/debian-lts-announce/2022/05/msg00002.html
https://lists.debian.org/debian-lts-announce/2025/03/msg00005.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GFXJ35WKPME4HYNQCQNAJHLCZOJL2SAE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R36OYC5SJ6FLPVAYJYYT4MOJ2I7MGYFF/

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