# CVE-2021-47224: linux: In the Linux kernel, the following vulnerability has been resolved:  net: ll_temac: Make sure to free skb when it is...

CVE-2021-47224 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47224, released May 21, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47224
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 21, 2024

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.10.46-1 | [DEBIAN-CVE-2021-47224](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47224.md) | May 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.10.46-1 | [DEBIAN-CVE-2021-47224](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47224.md) | May 21, 2024 |
| Linux | linux Debian 14 | 5.10.46-1 | [DEBIAN-CVE-2021-47224](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47224.md) | May 21, 2024 |

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