# CVE-2021-47111: linux: In the Linux kernel, the following vulnerability has been resolved:  xen-netback: take a reference to the RX task thr...

CVE-2021-47111 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47111, released March 15, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47111
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 15, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  xen-netback: take a reference to the RX task thread  Do this in order to prevent the task from being freed if the thread returns (which can be triggered by the frontend) before the call to kthread_stop done as part of the backend tear down. Not taking the reference will lead to a use-after-free in that scenario. Such reference was taken before but dropped as part of the rework done in 2ac061ce97f4.  Reintroduce the reference taking and add a comment this time explaining why it's needed.  This is XSA-374 / CVE-2021-28691.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.10.46-1 | [DEBIAN-CVE-2021-47111](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47111.md) | Mar 15, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.10.46-1 | [DEBIAN-CVE-2021-47111](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47111.md) | Mar 15, 2024 |
| Linux | linux Debian 14 | 5.10.46-1 | [DEBIAN-CVE-2021-47111](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47111.md) | Mar 15, 2024 |

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