CVE-2021-47652: video: fbdev: smscufx: Fix null-ptr-deref in ufx_usb_probe()

Severity: medium (CVSS 5.5 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: 2025-02-26 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: video: fbdev: smscufx: Fix null-ptr-deref in ufx_usb_probe() I got a null-ptr-deref report: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:fb_destroy_modelist+0x38/0x100 ... Call Trace: ufx_usb_probe.cold+0x2b5/0xac1 [smscufx] usb_probe_interface+0x1aa/0x3c0 [usbcore] really_probe+0x167/0x460 ... ret_from_fork+0x1f/0x30 If fb_alloc_cmap() fails in ufx_usb_probe(), fb_destroy_modelist() will be called to destroy modelist in the error handling path. But modelist has not been initialized yet, so it will result in null-ptr-deref. Initialize modelist before calling fb_alloc_cmap() to fix this bug.

Affected products

Linux kernel: from 3.2 before 4.9.311; from 4.10 before 4.14.276; from 4.15 before 4.19.238; from 4.20 before 5.4.189; from 5.5 before 5.10.110; from 5.11 before 5.15.33 — fixed in 4.14.276, 4.19.238, 4.9.311, 5.10.110, 5.15.33, 5.16.19

How to fix

Upgrade to a fixed version: Linux kernel 4.14.276, 4.19.238, 4.9.311, 5.10.110. Check the vendor advisory for mitigations.

References

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