CVE-2023-53683 in Linux
Summary
by MITRE • 10/07/2025
In the Linux kernel, the following vulnerability has been resolved:
fs: hfsplus: remove WARN_ON() from hfsplus_cat_{read,write}_inode()
syzbot is hitting WARN_ON() in hfsplus_cat_{read,write}_inode(), for
crafted filesystem image can contain bogus length. There conditions are not kernel bugs that can justify kernel to panic.
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Analysis
by VulDB Data Team • 03/01/2026
The vulnerability identified as CVE-2023-53683 resides within the Linux kernel's HFS+ filesystem implementation, specifically affecting the hfsplus_cat_read_inode and hfsplus_cat_write_inode functions. This issue represents a defensive programming flaw where the kernel was incorrectly employing WARN_ON() macros to handle malformed filesystem metadata rather than gracefully managing the error conditions. The vulnerability manifests when crafted filesystem images contain bogus length values that trigger kernel warnings, potentially leading to system instability or unintended kernel panics during filesystem operations. The root cause stems from the kernel's attempt to maintain strict validation checks that, while well-intentioned, do not account for the possibility of malformed or maliciously constructed filesystem images that may legitimately occur in certain operational contexts.
The technical flaw manifests in the HFS+ filesystem driver's catalog tree handling mechanism where the kernel performs validation checks on inode metadata structures. When the syzbot fuzzer or similar testing tools encounter filesystem images with corrupted or invalid length fields, the WARN_ON() macros trigger warnings that escalate to kernel panic conditions in production environments. This represents a violation of the principle of graceful degradation where system components should handle malformed input without crashing the entire kernel. The vulnerability is classified as a defensive programming error that does not represent a true kernel bug but rather an overzealous error handling mechanism that fails to distinguish between legitimate kernel errors and recoverable filesystem corruption scenarios. The issue directly relates to CWE-707 and CWE-129, representing improper handling of input validation and inadequate bounds checking in kernel space operations.
The operational impact of CVE-2023-53683 extends beyond simple system instability to potentially enable denial-of-service attacks against systems running HFS+ filesystems. Attackers could craft malicious filesystem images that trigger the WARN_ON() conditions, causing kernel panics and system crashes when these filesystems are mounted or accessed. This vulnerability particularly affects systems that mount HFS+ volumes, including Mac OS X filesystems or systems using HFS+ for data exchange, as well as embedded systems or virtual environments that may encounter such filesystem images. The risk is elevated in environments where filesystem images are not strictly controlled or validated, such as in testing scenarios, data recovery operations, or systems that process untrusted storage media. The vulnerability demonstrates a weakness in the kernel's error handling architecture that could be exploited to disrupt system availability, making it a significant concern for system administrators managing critical infrastructure.
Mitigation strategies for CVE-2023-53683 focus on removing the overly aggressive WARN_ON() macros that cause kernel panics during legitimate but malformed filesystem operations. The fix involves modifying the hfsplus_cat_read_inode and hfsplus_cat_write_inode functions to handle invalid length values gracefully rather than triggering kernel warnings that escalate to system crashes. System administrators should ensure their kernels are updated to versions containing this fix, typically found in kernel releases following the patch that removes the problematic WARN_ON() calls. The recommended approach aligns with ATT&CK technique T1499.004, which addresses defensive measures against system resource exhaustion and denial-of-service conditions. Additional mitigations include implementing proper filesystem validation procedures before mounting potentially untrusted HFS+ images, monitoring kernel logs for warning messages that may indicate attempted exploitation, and ensuring that filesystem drivers properly handle edge cases without causing system-wide failures. Organizations should also consider implementing filesystem integrity checking mechanisms and regular kernel updates to prevent similar vulnerabilities from being exploited in their operational environments.