CVE-2024-50088 in Linux
Summary
by MITRE • 10/29/2024
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix uninitialized pointer free in add_inode_ref()
The add_inode_ref() function does not initialize the "name" struct when it is declared. If any of the following calls to "read_one_inode() returns NULL,
dir = read_one_inode(root, parent_objectid); if (!dir) {
ret = -ENOENT; goto out; }
inode = read_one_inode(root, inode_objectid); if (!inode) {
ret = -EIO; goto out; }
then "name.name" would be freed on "out" before being initialized.
out: ... kfree(name.name);
This issue was reported by Coverity with CID 1526744.
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Analysis
by VulDB Data Team • 10/02/2025
The vulnerability identified as CVE-2024-50088 represents a critical memory management flaw within the btrfs file system implementation of the Linux kernel. This issue manifests in the add_inode_ref() function where a struct named "name" is declared without proper initialization before being used in memory deallocation operations. The flaw stems from improper handling of error conditions during inode reference addition operations, creating a scenario where uninitialized memory pointers could be dereferenced during cleanup operations.
The technical root cause of this vulnerability lies in the function's failure to initialize the name struct variable before potential early returns. When the read_one_inode() function calls fail and return NULL values, the control flow executes the error handling path that leads to kfree(name.name) being called. However, since name.name was never initialized, this results in attempting to free an uninitialized pointer, which can lead to undefined behavior and potential memory corruption. This pattern directly aligns with CWE-457: Use of Uninitialized Variable, which specifically addresses the dangers of using variables that have not been properly initialized before use.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential attack vector for privilege escalation and system stability compromise. An attacker who can manipulate btrfs file system operations to trigger the error path in add_inode_ref() could potentially exploit this uninitialized pointer dereference to execute arbitrary code or cause system crashes. The vulnerability is particularly concerning in environments where btrfs is actively used for storage management, as it could be leveraged to disrupt system operations or gain elevated privileges. This aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, where memory corruption vulnerabilities are commonly exploited to achieve elevated system access.
The fix for this vulnerability requires ensuring proper initialization of the name struct before any error handling paths are executed. The remediation involves adding explicit initialization of the name variable when it is declared, ensuring that even in error conditions, the memory deallocation operation will have valid pointer values. This approach directly addresses the fundamental issue of uninitialized memory access and prevents the potential for exploitation through controlled manipulation of btrfs operations. System administrators should prioritize applying kernel updates that contain this fix, particularly in environments where btrfs file systems are actively used, as the vulnerability represents a significant risk to system integrity and availability.