What’s Vulnerable › Vulnerabilities

CVE-2023-52837: nbd: fix uaf in nbd_open

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-05-21 · updated 2026-08-04
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: nbd: fix uaf in nbd_open Commit 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and blk_cleanup_disk") cleans up disk by blk_cleanup_disk() and it won't set disk->private_data as NULL as before. UAF may be triggered in nbd_open() if someone tries to open nbd device right after nbd_put() since nbd has been free in nbd_dev_remove(). Fix this by implementing ->free_disk and free private data in it.

Affected products

• Linux kernel: from 5.14 before 6.1.63; from 6.2 before 6.5.12; from 6.6 before 6.6.2 — fixed in 6.1.63, 6.5.12, 6.6.2

How to fix

Upgrade to a fixed version: Linux kernel 6.1.63, 6.5.12, 6.6.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/327462725b0f759f093788dfbcb2f1fd132f956b
• https://git.kernel.org/stable/c/4e9b3ec84dc97909876641dad14e0a2300d6c2a3
• https://git.kernel.org/stable/c/56bd7901b5e9dbc9112036ea615ebcba1565fafe
• https://git.kernel.org/stable/c/879947f4180bc6e83af64eb0515e0cf57fce15db
• https://git.kernel.org/stable/c/327462725b0f759f093788dfbcb2f1fd132f956b
• https://git.kernel.org/stable/c/4e9b3ec84dc97909876641dad14e0a2300d6c2a3
• https://git.kernel.org/stable/c/56bd7901b5e9dbc9112036ea615ebcba1565fafe
• https://git.kernel.org/stable/c/879947f4180bc6e83af64eb0515e0cf57fce15db

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