CVE-2021-47567: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/32: Fix hardlockup on vmap stack overflow Since the commit c118c7303ad5 ("powerpc/32: Fix vmap stack - Do not activate MMU before reading task struct") a vmap stack overflow results in a hard lockup. This is because emergency_ctx is still addressed with its virtual address allthough data MMU is not active anymore at that time. Fix it by using a physical address instead.

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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

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.9.5 — 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/5bb60ea611db1e04814426ed4bd1c95d1487678e https://git.kernel.org/stable/c/c4e3ff8b8b1d54f0c755670174c453b06e17114b https://git.kernel.org/stable/c/dfe906da9a1abebdebe8b15bb3e66a2578f6c4c7 https://git.kernel.org/stable/c/5bb60ea611db1e04814426ed4bd1c95d1487678e https://git.kernel.org/stable/c/c4e3ff8b8b1d54f0c755670174c453b06e17114b https://git.kernel.org/stable/c/dfe906da9a1abebdebe8b15bb3e66a2578f6c4c7

Frequently Asked Questions

What is CVE-2021-47567? +

In the Linux kernel, the following vulnerability has been resolved: powerpc/32: Fix hardlockup on vmap stack overflow Since the commit c118c7303ad5 ("powerpc/32: Fix vmap stack - Do not activate MMU before reading task struct") a vmap stack overflow results in a hard lockup. This is because emergency_ctx is still addressed with its virtual address allthough data MMU is not active anymore at that time. Fix it by using a physical address instead. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47567? +

CVE-2021-47567 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-2021-47567? +

CVE-2021-47567 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-2021-47567? +

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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CVE-2021-47567