Ubuntu 26.04 OpenVPN Critical Security Issues CVE-2026

Several security issues were fixed in OpenVPN. Software Description: - openvpn: virtual private network software Details: It was discovered that OpenVPN had a 1-byte buffer overrun when handling NTLMv2 proxy responses. An attacker could use this issue to cause a denial of service or possibly execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-11771) It was discovered that OpenVPN incorrectly handled metadata when extracting tls-crypt-v2 client keys. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-12932) It was discovered that OpenVPN had a use-after-free in the ack_write_buf handling. An attacker could use this issue to cause OpenVPN to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-12996) It was discovered that OpenVPN had a use-after-free in the tls_wrap_reneg handling. An attacker could use this issue to cause OpenVPN to crash, resulting in a denial of... Read the Full Advisory

Several security issues were fixed in OpenVPN.

Software Description:

- openvpn: virtual private network software

It was discovered that OpenVPN had a 1-byte buffer overrun when handling

NTLMv2 proxy responses. An attacker could use this issue to cause a denial

of service or possibly execute arbitrary code. This issue only affected

Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-11771)

It was discovered that OpenVPN incorrectly handled metadata when extracting

tls-crypt-v2 client keys. An attacker could possibly use this issue to

obtain sensitive information. (CVE-2026-12932)

It was discovered that OpenVPN had a use-after-free in the ack_write_buf

handling. An attacker could use this issue to cause OpenVPN to crash,

resulting in a denial of service, or possibly execute arbitrary code.

It was discovered that OpenVPN had a use-after-free in the tls_wrap_reneg

handling. An attacker could use this issue to cause OpenVPN to crash,

resulting in a denial of...

The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS openvpn 2.7.0-1ubuntu1.2 Ubuntu 24.04 LTS openvpn 2.6.19-0ubuntu0.24.04.3 Ubuntu 22.04 LTS openvpn 2.5.11-0ubuntu0.22.04.4 After a standard system update you need to restart OpenVPN to make all the necessary changes.

CVE-2026-11771, CVE-2026-12932, CVE-2026-12996, CVE-2026-13117,

CVE-2026-13122, CVE-2026-13698

Ubuntu Security Notice USN-8540-1

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