An out-of-bounds heap read and integer underflow in the TCP urgent data handling (sosendoob) in freedesktop.org libslirp version before v4.9.2 on hypervisor host environments (e.g., QEMU) allows a privileged guest VM attacker (root or CAP_NET_RAW) to leak gigabytes of sensitive host-process heap memory via sending crafted TCP segments with manipulated URG flags and urgent pointers (ti_urp).

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2026:0617 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    CVE-2026-9539:
    An out-of-bounds heap read and integer underflow in the TCP urgent data handling (sosendoob) in     freedesktop.org libslirp version before v4.9.2 on hypervisor host environments (e.g., QEMU) allows a     privileged guest VM attacker (root or CAP_NET_RAW) to leak gigabytes of sensitive host-process heap memory     via sending crafted TCP segments with manipulated URG flags and urgent pointers (ti_urp).

Tenable has extracted the preceding description block directly from the Tencent Linux 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 Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-8550-1 advisory.

    It was discovered that libslirp incorrectly handled TCP urgent data. A privileged attacker inside a guest     VM could possibly use this issue to obtain sensitive information from the host process memory.

Tenable has extracted the preceding description block directly from the Ubuntu 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 a vulnerability as referenced in the SUSE-SU-2026:2931-1 advisory.

    - CVE-2026-9539: TCP URG out of bounds heap read information leak (bsc#1268903).

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 openSUSE 16 host has packages installed that are affected by a vulnerability as referenced in the openSUSE- SU-2026:21216-1 advisory.

    This update for libslirp fixes the following issue

    - CVE-2026-9539: TCP URG out of bounds heap read information leak (bsc#1268903).

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

  - An out-of-bounds heap read and integer underflow in the TCP urgent data handling (sosendoob) in     freedesktop.org libslirp version before v4.9.2 on hypervisor host environments (e.g., QEMU) allows a     privileged guest VM attacker (root or CAP_NET_RAW) to leak gigabytes of sensitive host-process heap memory     via sending crafted TCP segments with manipulated URG flags and urgent pointers (ti_urp). (CVE-2026-9539)

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

ID	Name	Product	Family	Severity
328401	TencentOS Server 4: libslirp (TSSA-2026:0617)	Nessus	Tencent Local Security Checks	medium
327333	Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS : libslirp vulnerability (USN-8550-1)	Nessus	Ubuntu Local Security Checks	medium
326934	SUSE SLED15 / SLES15 Security Update : libslirp (SUSE-SU-2026:2931-1)	Nessus	SuSE Local Security Checks	medium
325023	openSUSE 16 Security Update : libslirp (openSUSE-SU-2026:21216-1)	Nessus	SuSE Local Security Checks	medium
322444	Linux Distros Unpatched Vulnerability : CVE-2026-9539	Nessus	Misc.	medium

Detections

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CVE-2026-9539

medium

Tenable Plugins

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medium

medium

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medium