openvpn vulnerabilities

CVE-2026-106017

Improper certificate validation in the OpenVPN 3 Core library version 3.4 through 3.11.7 allows attackers to circumvent extended key usage restrictions.

CVE-2026-84471

The fix for CVE-2026-12996 was incomplete. A use-after-free in OpenVPN 2.6.0 through 2.6.22 and 2.7_alpha1 through 2.7.7 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry.

CVE-2026-84790

OpenVPN 2.7_alpha1 through 2.7.7 allows remote authenticated users to impersonate others via a crafted certificate subject field

CVE-2026-84732

Retransmissions of ACK packet ID in OpenVPN through 2.6.22 and 2.7.6 allow remote unauthenticated attackers to cause a denial of service via crafted inputs that trigger a timeout integer overflow

CVE-2026-12932

A memory leak in the tls-crypt-v2 client key extraction in OpenVPN 2.5.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers to cause a denial of service (memory exhaustion) via a flood of crafted packets

CVE-2026-12996

A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry

CVE-2026-13698

A memory leak in OpenVPN version 2.5.0 through 2.5.11, 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote attackers with a valid tls-crypt-v2 client key to potentially cause a denial of service

CVE-2026-40215

A race condition in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows remote attackers to potentially cause a server crash or leak heap memory via a use-after-free triggered during TLS session promotion.

CVE-2026-35058

Improper validation of packet length during tls-crypt-v2 key extraction in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows authenticated attackers to trigger a fatal assertion and cause a denial of service via a specially crafted packet.

CVE-2024-5594

OpenVPN before 2.6.11 does not santize PUSH_REPLY messages properly which an attacker controlling the server can use to inject unexpected arbitrary data ending up in client logs.

• Update to 2.4.12-0ubuntu0.20.04.2

DHCP routing options can manipulate interface-based VPN traffic

DHCP can add routes to a client’s routing table via the classless static route option (121). VPN-based security solutions that rely on routes to redirect traffic can be forced to leak traffic over the physical interface. An attacker on the same local network can read, disrupt, or possibly modify network traffic that was expected to be protected by the VPN.

CVE-2020-20813

Control Channel in OpenVPN 2.4.7 and earlier allows remote attackers to cause a denial of service via crafted reset packet.

CVE-2022-0547

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.

• Update to 2.4.7-1ubuntu2.20.04.4

CVE-2020-15078

OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control channel data on servers configured with deferred authentication, which can be used to potentially trigger further information leaks.

• Update to 2.4.7-1ubuntu2.20.04.2

CVE-2020-11810

An issue was discovered in OpenVPN 2.4.x before 2.4.9. An attacker can inject a data channel v2 (P_DATA_V2) packet using a victim's peer-id. Normally such packets are dropped, but if this packet arrives before the data channel crypto parameters have been initialized, the victim's connection will be dropped. This requires careful timing due to the small time window (usually within a few seconds) between the victim client connection starting and the server PUSH_REPLY response back to the client. This attack will only work if Negotiable Cipher Parameters (NCP) is in use.

• Update to 2.4.7-1ubuntu2.20.04.2