CVE-2021-46968: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: fix zcard and zqueue hot-unplug memleak Tests with kvm and a kmemdebug kernel showed, that on hot unplug the zcard and zqueue structs for the unplugged card or queue are not properly freed because of a mismatch with get/put for the embedded kref counter. This fix now adjusts the handling of the kref counters. With init the kref counter starts with 1. This initial value needs to drop to zero with the unregister of the card or queue to trigger the release and free the object.

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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-401 CWE-401

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.10 — 5.10.36
linux	linux_kernel	5.11 — 5.11.20
linux	linux_kernel	5.12 — 5.12.3

References

Advisories & Patches

https://git.kernel.org/stable/c/026499a9c2e002e621ad568d1378324ae97e5524 https://git.kernel.org/stable/c/055a063a18bcd19b93709e3eac8078d6b2f04599 https://git.kernel.org/stable/c/70fac8088cfad9f3b379c9082832b4d7532c16c2 https://git.kernel.org/stable/c/971dc8706cee47393d393905d294ea47e39503d3 https://git.kernel.org/stable/c/026499a9c2e002e621ad568d1378324ae97e5524 https://git.kernel.org/stable/c/055a063a18bcd19b93709e3eac8078d6b2f04599 https://git.kernel.org/stable/c/70fac8088cfad9f3b379c9082832b4d7532c16c2 https://git.kernel.org/stable/c/971dc8706cee47393d393905d294ea47e39503d3

Frequently Asked Questions

What is CVE-2021-46968? +

In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: fix zcard and zqueue hot-unplug memleak Tests with kvm and a kmemdebug kernel showed, that on hot unplug the zcard and zqueue structs for the unplugged card or queue are not properly freed because of a mismatch with get/put for the embedded kref counter. This fix now adjusts the handling of the kref counters. With init the kref counter starts with 1. This initial value needs to drop to zero with the unregister of the card or queue to trigger the release and free the object. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-46968? +

CVE-2021-46968 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-2021-46968? +

CVE-2021-46968 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-2021-46968? +

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-2021-46968