The Linux Kernel is the core of the GNU/Linux operating system that provides many critical features like process management, memory management, and interacting with hardware devices. With the frequent release of software updates, many security vulnerabilities are frequently identified and patched to ensure the operating system's security. One such vulnerability is the Use After Free vulnerability recently found and assigned CVE-2023-2985.


CVE-2023-2985 refers to a use-after-free flaw identified in the 'hfsplus_put_super()' function within the 'fs/hfsplus/super.c' file in the Linux Kernel's HFS+ file system implementation. This vulnerability could potentially be exploited by a local attacker to cause a denial of service (DoS) problem on a system running Linux. The Use After Free flaw is related to memory management, allowing attackers to access memory that has already been freed, potentially leading to unintended behavior.

The problematic code snippet from 'fs/hfsplus/super.c' file is as follows

static void hfsplus_put_super(struct super_block *sb)
    struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);



In this function, the kernel frees the memory allocated for sbi->s_vhdr and sbi->s_avhdr, followed by an iput() operation on sbi->hidden_dir. The use-after-free flaw occurs when the kernel continues to access the sbi structure even after it has been freed in the code. This can potentially lead to unintended behavior, crashing the system or execution of arbitrary code.

Exploit Details

Although there are no known exploits for this vulnerability in the wild, it potentially allows an attacker to exploit the Use After Free issue by performing the following steps:

1. The attacker writes a malicious code, a program, or a script that triggers the use-after-free flaw by accessing the memory previously allocated for sbi structure.

The attacker gains low-privileged access to a target Linux system running an HFS+ file system.

3. The attacker runs the crafted code on the target system, potentially causing a denial of service or arbitrary code execution.

Original References

The vulnerability was initially reported by security researcher Michael Davidson. The original references for this vulnerability can be found in the Linux Kernel Mailing List (LKML) post:



To mitigate this use-after-free vulnerability (CVE-2023-2985), users are advised to regularly update their Linux systems, including the kernel. Most major Linux distributions provide security updates that address such vulnerabilities. It is important to apply patches as soon as they are made available by the maintainers.


CVE-2023-2985 highlights the importance of staying up-to-date with security patches and taking proactive measures to ensure system security. Although no known exploits have been found in the wild, it's crucial to address such vulnerabilities promptly. By updating the Linux kernel regularly, users and administrators can ensure their systems remain protected against threats like this Use After Free flaw and any other potential attack vectors.


Published on: 06/01/2023 01:15:00 UTC
Last modified on: 06/07/2023 19:00:00 UTC