CVE-2021-47239: net: usb: fix possible use-after-free in smsc75xx_bind

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-06-17
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: fix possible use-after-free in smsc75xx_bind The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind") fails to clean up the work scheduled in smsc75xx_reset-> smsc75xx_set_multicast, which leads to use-after-free if the work is scheduled to start after the deallocation. In addition, this patch also removes a dangling pointer - dev->data[0]. This patch calls cancel_work_sync to cancel the scheduled work and set the dangling pointer to NULL.

Affected products

Linux kernel: from 4.4.271 before 4.4.274; from 4.9.271 before 4.9.274; from 4.14.235 before 4.14.238; from 4.19.193 before 4.19.196; from 5.4.124 before 5.4.128; from 5.10.42 before 5.10.46 — fixed in 4.14.238, 4.19.196, 4.4.274, 4.9.274, 5.10.46, 5.12.13

How to fix

Upgrade to a fixed version: Linux kernel 4.14.238, 4.19.196, 4.4.274, 4.9.274. Check the vendor advisory for mitigations.

References

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