CVE-2021-47113: linux kernel Use-After-Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: abort in rename_exchange if we fail to insert the second ref Error injection stress uncovered a problem where we'd leave a dangling inode ref if we failed during a rename_exchange. This happens because we insert the inode ref for one side of the rename, and then for the other side. If this second inode ref insert fails we'll leave the first one dangling and leave a corrupt file system behind. Fix this by aborting if we did the insert for the first inode ref.

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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-416 Use After Free

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 5.10.43
linux	linux_kernel	5.11 — 5.12.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/0df50d47d17401f9f140dfbe752a65e5d72f9932 https://git.kernel.org/stable/c/dc09ef3562726cd520c8338c1640872a60187af5 https://git.kernel.org/stable/c/ff8de2cec65a8c8521faade12a31b39c80e49f5b https://git.kernel.org/stable/c/0df50d47d17401f9f140dfbe752a65e5d72f9932 https://git.kernel.org/stable/c/dc09ef3562726cd520c8338c1640872a60187af5 https://git.kernel.org/stable/c/ff8de2cec65a8c8521faade12a31b39c80e49f5b

Frequently Asked Questions

What is CVE-2021-47113? +

In the Linux kernel, the following vulnerability has been resolved: btrfs: abort in rename_exchange if we fail to insert the second ref Error injection stress uncovered a problem where we'd leave a dangling inode ref if we failed during a rename_exchange. This happens because we insert the inode ref for one side of the rename, and then for the other side. If this second inode ref insert fails we'll leave the first one dangling and leave a corrupt file system behind. Fix this by aborting if we did the insert for the first inode ref. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47113? +

CVE-2021-47113 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-2021-47113? +

CVE-2021-47113 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-2021-47113? +

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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