CVE-2023-53055: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: fscrypt: destroy keyring after security_sb_delete() fscrypt_destroy_keyring() must be called after all potentially-encrypted inodes were evicted; otherwise it cannot safely destroy the keyring. Since inodes that are in-use by the Landlock LSM don't get evicted until security_sb_delete(), this means that fscrypt_destroy_keyring() must be called *after* security_sb_delete(). This fixes a WARN_ON followed by a NULL dereference, only possible if Landlock was being used on encrypted files.

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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	5.10.154 — 5.11
linux	linux_kernel	5.15.78 — 5.15.105
linux	linux_kernel	6.0.8 — 6.1.22
linux	linux_kernel	6.2 — 6.2.9
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/497ab5d9c7852dfedab2c9de75e41b60e54b7c5d https://git.kernel.org/stable/c/992a3f3e8a0c92151dfdf65fc85567c865fd558a https://git.kernel.org/stable/c/ccb820dc7d2236b1af0d54ae038a27b5b6d5ae5a https://git.kernel.org/stable/c/d77531fac6a1fd9f1db0195438ba5419d72b96c4

Frequently Asked Questions

What is CVE-2023-53055? +

In the Linux kernel, the following vulnerability has been resolved: fscrypt: destroy keyring after security_sb_delete() fscrypt_destroy_keyring() must be called after all potentially-encrypted inodes were evicted; otherwise it cannot safely destroy the keyring. Since inodes that are in-use by the Landlock LSM don't get evicted until security_sb_delete(), this means that fscrypt_destroy_keyring() must be called *after* security_sb_delete(). This fixes a WARN_ON followed by a NULL dereference, only possible if Landlock was being used on encrypted files. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2023-53055? +

CVE-2023-53055 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-2023-53055? +

CVE-2023-53055 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-2023-53055? +

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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