# CVE-2022-49300: linux: In the Linux kernel, the following vulnerability has been resolved:  nbd: fix race between nbd_alloc_config() and mod...

CVE-2022-49300 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49300, released February 26, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-49300
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 26, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  nbd: fix race between nbd_alloc_config() and module removal  When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it.  The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below:    BUG: kernel NULL pointer dereference, address: 0000000000000040   Oops: 0000 [#1] SMP PTI   CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)   Workqueue: knbd16-recv recv_work [nbd]   RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd]   Call Trace:    recv_work+0x3b/0xb0 [nbd]    process_one_work+0x1ed/0x390    worker_thread+0x4a/0x3d0    kthread+0x12a/0x150    ret_from_fork+0x22/0x30  Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd->config only when nbd_alloc_config() succeeds to ensure the value of nbd->config is binary (valid or NULL).  Also adding a debug message to check the reference counter of nbd_config during module removal.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.18.5-1 | [DEBIAN-CVE-2022-49300](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49300.md) | Feb 26, 2025 |
| Linux | linux Debian 13.5 (trixie) | 5.18.5-1 | [DEBIAN-CVE-2022-49300](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49300.md) | Feb 26, 2025 |
| Linux | linux Debian 14 | 5.18.5-1 | [DEBIAN-CVE-2022-49300](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49300.md) | Feb 26, 2025 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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