In the Linux kernel, the following vulnerability has been resolved: net: ll_temac: Make sure to free skb when it is completely used With the skb pointer piggy-backed on the TX BD, we have a simple and efficient way to free the skb buffer when the frame has been transmitted. But in order to avoid freeing the skb while there are still fragments from the skb in use, we need to piggy-back on the TX BD of the skb, not the first. Without this, we are doing use-after-free on the DMA side, when the first BD of a multi TX BD packet is seen as completed in xmit_done, and the remaining BDs are still being processed.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-989762 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    net: ll_temac: Make sure to free skb when it is completely used

    With the skb pointer piggy-backed on the TX BD, we have a simple and     efficient way to free the skb buffer when the frame has been transmitted.
    But in order to avoid freeing the skb while there are still fragments from     the skb in use, we need to piggy-back on the TX BD of the skb, not the     first.

    Without this, we are doing use-after-free on the DMA side, when the first     BD of a multi TX BD packet is seen as completed in xmit_done, and the     remaining BDs are still being processed.

Tenable has extracted the preceding description block directly from the Unity 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 Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2025-987094 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    net: ll_temac: Make sure to free skb when it is completely used

    With the skb pointer piggy-backed on the TX BD, we have a simple and     efficient way to free the skb buffer when the frame has been transmitted.
    But in order to avoid freeing the skb while there are still fragments from     the skb in use, we need to piggy-back on the TX BD of the skb, not the     first.

    Without this, we are doing use-after-free on the DMA side, when the first     BD of a multi TX BD packet is seen as completed in xmit_done, and the     remaining BDs are still being processed.

Tenable has extracted the preceding description block directly from the Unity 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 Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - net: ll_temac: Make sure to free skb when it is completely used With the skb pointer piggy-backed on the     TX BD, we have a simple and efficient way to free the skb buffer when the frame has been transmitted. But     in order to avoid freeing the skb while there are still fragments from the skb in use, we need to piggy-     back on the TX BD of the skb, not the first. Without this, we are doing use-after-free on the DMA side,     when the first BD of a multi TX BD packet is seen as completed in xmit_done, and the remaining BDs are     still being processed. (CVE-2021-47224)

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

ID	Name	Product	Family	Severity
273087	Unity Linux 20.1070a Security Update: kernel (UTSA-2025-989762)	Nessus	Unity Linux Local Security Checks	medium
268542	Unity Linux 20.1070e Security Update: kernel (UTSA-2025-987094)	Nessus	Unity Linux Local Security Checks	medium
245612	Linux Distros Unpatched Vulnerability : CVE-2021-47224	Nessus	Misc.	medium

Detections

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CVE-2021-47224

medium

Tenable Plugins

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medium

medium