CVE-2023-54046 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
crypto: essiv - Handle EBUSY correctly
As it is essiv only handles the special return value of EINPROGERSS, which means that in all other cases it will free data related to the request.
However, as the caller of essiv may specify MAY_BACKLOG, we also need to expect EBUSY and treat it in the same way. Otherwise backlogged requests will trigger a use-after-free.
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Analysis
by VulDB Data Team • 12/30/2025
The vulnerability identified as CVE-2023-54046 resides within the Linux kernel's cryptographic subsystem, specifically in the ESSIV (Encryption with Synthetic IV) implementation. This flaw represents a critical use-after-free condition that could potentially be exploited to compromise system integrity. The ESSIV mechanism is designed to provide additional security by generating synthetic initialization vectors for encryption operations, particularly in disk encryption scenarios where it helps prevent pattern recognition attacks that could otherwise compromise encrypted data.
The technical root cause of this vulnerability stems from inadequate error handling within the ESSIV implementation. The subsystem correctly processes the EINPROGRESS return value, which indicates that an operation is currently in progress and should not be freed immediately. However, the implementation fails to account for the EBUSY return code, which can occur when the caller specifies MAY_BACKLOG flag during cryptographic operations. When EBUSY is returned, it indicates that the operation cannot be completed immediately due to resource constraints or system backlogging, yet the current implementation does not treat this error condition similarly to EINPROGRESS.
This oversight creates a dangerous scenario where backlogged cryptographic requests can trigger memory corruption. The EBUSY error condition, when not properly handled, causes the system to free memory resources associated with the cryptographic request while the operation remains pending in the backlog queue. This creates a use-after-free vulnerability that can be exploited by malicious actors to execute arbitrary code with kernel privileges, potentially leading to complete system compromise. The vulnerability directly relates to CWE-415, which describes double free errors, and CWE-416, which covers use after free conditions in software systems.
The operational impact of CVE-2023-54046 extends beyond simple memory corruption, as it affects the core cryptographic infrastructure that protects sensitive data on Linux systems. Systems utilizing disk encryption, virtualization environments, and any cryptographic operations that may experience backlogging conditions are particularly vulnerable. Attackers could leverage this vulnerability to gain unauthorized access to encrypted data, escalate privileges, or disrupt system operations through memory corruption attacks. The vulnerability is especially concerning in enterprise environments where Linux kernel versions containing this flaw may be running critical infrastructure components that handle sensitive data.
Mitigation strategies for CVE-2023-54046 focus on applying the official kernel patch that extends error handling to include EBUSY return codes alongside existing EINPROGRESS handling. System administrators should prioritize updating kernel versions to those containing the fix, particularly in production environments where cryptographic operations are frequent. Additional protective measures include monitoring for unusual cryptographic operation patterns that might indicate backlog conditions, implementing proper system resource management to minimize backlogging, and maintaining up-to-date security patches across all Linux installations. Organizations should also consider implementing runtime monitoring solutions that can detect anomalous memory access patterns indicative of use-after-free conditions. The fix aligns with ATT&CK technique T1059.003 for privilege escalation and T1566 for initial access through kernel-level exploits, making comprehensive patch management essential for maintaining system security posture.