CVE-2021-47652: linux kernel Null Dereference — Fix

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	3.2 — 4.9.311
linux	linux_kernel	4.10 — 4.14.276
linux	linux_kernel	4.15 — 4.19.238
linux	linux_kernel	4.20 — 5.4.189
linux	linux_kernel	5.5 — 5.10.110
linux	linux_kernel	5.11 — 5.15.33
linux	linux_kernel	5.16 — 5.16.19
linux	linux_kernel	5.17 — 5.17.2

References

Advisories & Patches

Frequently Asked Questions

What is CVE-2021-47652? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47652? +

CVE-2021-47652 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-47652? +

CVE-2021-47652 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47652? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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