Linux Kernel up to 5.15.104/6.1.21/6.2.8 fscrypt security_sb_delete null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.15.104/6.1.21/6.2.8. It has been classified as critical. Impacted is the function security_sb_delete of the component fscrypt. The manipulation leads to null pointer dereference. This vulnerability is referenced as CVE-2023-53055. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 5.15.104/6.1.21/6.2.8. This issue affects the function security_sb_delete of the component fscrypt. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

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 is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2023-53055 since 05/02/2025. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 241778 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1054)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.105, 6.1.22 or 6.2.9 eliminates this vulnerability. Applying the patch 992a3f3e8a0c92151dfdf65fc85567c865fd558a/d77531fac6a1fd9f1db0195438ba5419d72b96c4/497ab5d9c7852dfedab2c9de75e41b60e54b7c5d/ccb820dc7d2236b1af0d54ae038a27b5b6d5ae5a is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (241778). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.104
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.2.4
• 6.2.5
• 6.2.6
• 6.2.7
• 6.2.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion