Ubuntu 26.04 OpenVPN Critical Denial of Service Threat USN-8852

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Several security issues were fixed in OpenVPN. Software Description: - openvpn: virtual private network software Details: It was discovered that OpenVPN had a use-after-free vulnerability in its TLS session handling. An attacker could possibly use this issue to cause OpenVPN to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-84471) It was discovered that OpenVPN incorrectly handled retransmissions of ACK packet IDs, which could trigger a timeout integer overflow. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2026-84732)

Several security issues were fixed in OpenVPN.

Software Description:

- openvpn: virtual private network software

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

its TLS session handling. An attacker could possibly use this issue

to cause OpenVPN to crash, resulting in a denial of service, or

execute arbitrary code. (CVE-2026-84471)

It was discovered that OpenVPN incorrectly handled retransmissions of

ACK packet IDs, which could trigger a timeout integer overflow. A

remote attacker could possibly use this issue to cause a denial of

service. (CVE-2026-84732)

The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS openvpn 2.7.0-1ubuntu1.3 Ubuntu 24.04 LTS openvpn 2.6.19-0ubuntu0.24.04.4 Ubuntu 22.04 LTS openvpn 2.5.11-0ubuntu0.22.04.5 After a standard system update you need to restart OpenVPN to make all the necessary changes.

CVE-2026-84471, CVE-2026-84732

Ubuntu Security Notice USN-8852-1

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