# CVE-2022-49755: linux: In the Linux kernel, the following vulnerability has been resolved:  usb: gadget: f_fs: Prevent race during ffs_ep0_q...

CVE-2022-49755 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49755, released March 27, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2022-49755
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 27, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait  While performing fast composition switch, there is a possibility that the process of ffs_ep0_write/ffs_ep0_read get into a race condition due to ep0req being freed up from functionfs_unbind.  Consider the scenario that the ffs_ep0_write calls the ffs_ep0_queue_wait by taking a lock &ffs->ev.waitq.lock. However, the functionfs_unbind isn't bounded so it can go ahead and mark the ep0req to NULL, and since there is no NULL check in ffs_ep0_queue_wait we will end up in use-after-free.  Fix this by making a serialized execution between the two functions using a mutex_lock(ffs->mutex).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.11-1 | [DEBIAN-CVE-2022-49755](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49755.md) | Mar 27, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.1.11-1 | [DEBIAN-CVE-2022-49755](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49755.md) | Mar 27, 2025 |
| Linux | linux Debian 14 | 6.1.11-1 | [DEBIAN-CVE-2022-49755](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49755.md) | Mar 27, 2025 |

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