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

The remote Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8852-1 advisory.

    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)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4217-1 advisory.

    - CVE-2026-63650: OpenVPN 2.7_alpha1 through 2.7.5 using mbedTLS allows remote authenticated users to be     misidentified       by ignoring the configured X.509 username identity lookup field (bsc#1275310).
    - CVE-2026-84732: Remote Denial of Service via crafted ACK packets (bsc#1279613).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES12 / SLES_SAP12 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:4242-1 advisory.

    This update for openvpn fixes the following issue:

    - CVE-2026-84732: Remote Denial of Service via crafted ACK packets (bsc#1279613).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4213-1 advisory.

    - CVE-2026-63650: OpenVPN 2.7_alpha1 through 2.7.5 using mbedTLS allows remote authenticated users to be     misidentified       by ignoring the configured X.509 username identity lookup field (bsc#1275310).
    - CVE-2026-84732: Remote Denial of Service via crafted ACK packets (bsc#1279613).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 25012057-a886-11f1-a836-b42e991fc52e advisory.

    OpenVPN team reports:

              OpenVPN 2.x allows attackers to potentially cause a denial               of service against the control channel reliability layer,               either by driving the reliable TLS retransmission timeout               to grow without bound, or by sending acknowledgements for               packets that cannot be outstanding.


Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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-2026-84732)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
358414	Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS : OpenVPN vulnerabilities (USN-8852-1)	Nessus	Ubuntu Local Security Checks	Local	high
347902	SUSE SLES15 Security Update : openvpn (SUSE-SU-2026:4217-1)	Nessus	SuSE Local Security Checks	Local	high
347898	SUSE SLES12 Security Update : openvpn (SUSE-SU-2026:4242-1)	Nessus	SuSE Local Security Checks	Local	high
346802	SUSE SLED15: openvpn / openvpn-auth-pam-plugin / openvpn-dco / openvpn-dco-devel / etc (SUSE-SU-2026:4213-1)	Nessus	SuSE Local Security Checks	Local	high
343111	FreeBSD : OpenVPN: denial of service (25012057-a886-11f1-a836-b42e991fc52e)	Nessus	FreeBSD Local Security Checks	Local	high
342763	Linux Distros Unpatched Vulnerability : CVE-2026-84732	Nessus	Misc.	Local	high

Detections

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CVE-2026-84732

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Tenable Plugins

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