CVE-2025-22114 in Linux
Summary
by MITRE • 04/16/2025
In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't clobber ret in btrfs_validate_super()
Commit 2a9bb78cfd36 ("btrfs: validate system chunk array at btrfs_validate_super()") introduces a call to validate_sys_chunk_array() in btrfs_validate_super(), which clobbers the value of ret set earlier. This has the effect of negating the validity checks done earlier, making it so btrfs could potentially try to mount invalid filesystems.
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Analysis
by VulDB Data Team • 02/15/2026
The vulnerability identified as CVE-2025-22114 represents a critical flaw in the Linux kernel's btrfs filesystem implementation that compromises the integrity of filesystem validation processes. This issue specifically affects the btrfs_validate_super() function where a logical error occurs during the validation sequence that undermines the security posture of the filesystem. The vulnerability was introduced through commit 2a9bb78cfd36 which attempted to enhance system chunk array validation but inadvertently created a regression in the validation logic.
The technical flaw manifests in the btrfs_validate_super() function where the return value ret is overwritten by the validate_sys_chunk_array() call without preserving the earlier validation results. This clobbering behavior effectively neutralizes all previous validation checks that would have detected corrupted or malformed filesystem structures. The vulnerability creates a condition where the filesystem mount process can proceed with invalid or compromised data, potentially allowing unauthorized access or data corruption scenarios. This flaw directly impacts the kernel's ability to perform proper filesystem integrity verification during the mount operation.
The operational impact of this vulnerability extends beyond simple filesystem corruption as it represents a fundamental breakdown in the kernel's defensive mechanisms. When btrfs attempts to mount a filesystem, the validation sequence should fail early if any structural inconsistencies are detected, preventing the system from operating on potentially malicious or corrupted data. However, due to the return value clobbering, these early detection mechanisms are bypassed, allowing the mount operation to continue with invalid filesystem metadata. This creates a window where attackers could potentially exploit the filesystem by crafting malicious superblocks that would pass validation but cause system instability or security breaches.
From a cybersecurity perspective, this vulnerability aligns with CWE-284 Access Control Issues and represents a failure in proper error handling and validation sequence management. The flaw demonstrates poor defensive programming practices where intermediate validation results are not properly preserved, creating a security boundary that can be easily circumvented. The vulnerability has implications for the ATT&CK framework under T1068 Exploitation for Privilege Escalation and T1490 Inhibit System Recovery as it could enable attackers to manipulate filesystem structures to gain elevated privileges or cause system instability. Organizations relying on btrfs filesystems for critical data storage face potential risks including data integrity compromise and unauthorized access to sensitive information.
The recommended mitigations for this vulnerability include immediate application of kernel patches that address the return value handling in btrfs_validate_super() function. System administrators should prioritize updating their kernel versions to include the fixed commit that preserves the validation results before calling validate_sys_chunk_array(). Additionally, organizations should implement monitoring for unusual filesystem mount operations or error conditions that might indicate exploitation attempts. Regular filesystem integrity checks should be performed to detect any potential corruption that might have occurred before patching. The fix should be applied across all systems running affected kernel versions to ensure comprehensive protection against this validation bypass vulnerability.