PT-2024-10334 · Linux+3 · Linux Kernel+3
Sun Ke
·
Published
2024-02-28
·
Updated
2024-12-06
·
CVE-2021-46981
CVSS v3.1
5.5
Medium
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel versions prior to 5.11.0-rc5-00040-g76c057c84d28
Description
The vulnerability is related to a NULL pointer dereference in the
flush workqueue function when disconnecting from a network block device (/dev/nbdX). The issue occurs when the config refs is 1 and the pointers in nbd device are still null. This can lead to a kernel crash. The vulnerability can be exploited by an attacker to cause a denial-of-service (DoS) condition.To fix the issue, add a check for
nbd->recv workq in the nbd disconnect and put function.Recommendations
For Linux kernel versions prior to 5.11.0-rc5-00040-g76c057c84d28, add if
(nbd->recv workq) to nbd disconnect and put().Exploit
Fix
NULL Pointer Dereference
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Weakness Enumeration
Related Identifiers
Affected Products
Astra Linux
Linux Kernel
Suse
Ubuntu