CVE-2021-47560: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum: Protect driver from buggy firmware When processing port up/down events generated by the device's firmware, the driver protects itself from events reported for non-existent local ports, but not the CPU port (local port 0), which exists, but lacks a netdev. This can result in a NULL pointer dereference when calling netif_carrier_{on,off}(). Fix this by bailing early when processing an event reported for the CPU port. Problem was only observed when running on top of a buggy emulator.

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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	5.4 — 5.10.83
linux	linux_kernel	5.11 — 5.15.6
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/63b08b1f6834bbb0b4f7783bf63b80c8c8e9a047 https://git.kernel.org/stable/c/90d0736876c50ecde1a3275636a06b9ddb1cace9 https://git.kernel.org/stable/c/da4d70199e5d82da664a80077508d6c18f5e76df https://git.kernel.org/stable/c/63b08b1f6834bbb0b4f7783bf63b80c8c8e9a047 https://git.kernel.org/stable/c/90d0736876c50ecde1a3275636a06b9ddb1cace9 https://git.kernel.org/stable/c/da4d70199e5d82da664a80077508d6c18f5e76df

Frequently Asked Questions

What is CVE-2021-47560? +

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum: Protect driver from buggy firmware When processing port up/down events generated by the device's firmware, the driver protects itself from events reported for non-existent local ports, but not the CPU port (local port 0), which exists, but lacks a netdev. This can result in a NULL pointer dereference when calling netif_carrier_{on,off}(). Fix this by bailing early when processing an event reported for the CPU port. Problem was only observed when running on top of a buggy emulator. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47560? +

CVE-2021-47560 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-2021-47560? +

CVE-2021-47560 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-2021-47560? +

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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