CVE-2023-53568 in Linux
Summary
by MITRE • 10/04/2025
In the Linux kernel, the following vulnerability has been resolved:
s390/zcrypt: don't leak memory if dev_set_name() fails
When dev_set_name() fails, zcdn_create() doesn't free the newly allocated resources. Do it.
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Analysis
by VulDB Data Team • 03/02/2026
The vulnerability CVE-2023-53568 represents a memory leak issue within the Linux kernel's s390/zcrypt subsystem, specifically affecting IBM z/Architecture systems that utilize cryptographic hardware acceleration. This flaw occurs in the zcrypt driver responsible for managing cryptographic operations on IBM mainframe systems. The vulnerability manifests when the dev_set_name() function fails during device creation operations, leaving allocated memory resources unreleased and potentially causing system instability over time. The root cause lies in the improper error handling within the zcdn_create() function, which fails to implement proper resource cleanup when device name assignment encounters failures. This type of memory leak directly impacts system resource management and can lead to progressive memory exhaustion, particularly in environments where cryptographic operations are frequently performed. The issue demonstrates a classic lack of defensive programming practices in kernel space code where error conditions are not properly handled to ensure resource cleanup.
The technical implementation of this vulnerability involves the s390/zcrypt subsystem's device management logic where cryptographic devices are created and registered with the kernel's device model. When dev_set_name() fails to assign a device name to a newly allocated zcrypt device structure, the function should ensure that all previously allocated memory is freed before returning the error condition. However, the current implementation lacks this crucial cleanup step, resulting in memory leaks that accumulate over time as multiple device creation attempts are made. The vulnerability is classified as a memory leak under CWE-401, which specifically addresses improper management of allocated memory resources. This flaw affects the kernel's device management subsystem and can be exploited through repeated device creation operations that intentionally trigger the dev_set_name() failure condition. The operational impact is particularly concerning in high-throughput cryptographic environments where the system performs frequent device initialization and cleanup operations.
The operational consequences of CVE-2023-53568 extend beyond simple memory consumption issues to potentially compromise system stability and performance. In IBM mainframe environments, where cryptographic operations are critical for security and compliance, this memory leak can lead to progressive resource degradation that may eventually cause system crashes or performance degradation. The vulnerability affects systems running Linux kernels with s390/zcrypt support, particularly those implementing cryptographic hardware acceleration for tasks such as SSL/TLS operations, data encryption, and digital signature processing. Attackers could potentially exploit this weakness by repeatedly triggering device creation failures to accelerate memory exhaustion, though the direct attack surface is limited to kernel-level operations. The vulnerability aligns with ATT&CK technique T1070.004, which covers "Indicator Removal on Host: File Deletion" in the context of resource management failures. This memory leak represents a degradation of system integrity rather than a direct security compromise, but it can contribute to broader system instability that may be exploited by adversaries seeking to cause denial of service conditions.
Mitigation strategies for CVE-2023-53568 primarily involve applying the kernel patch that ensures proper resource cleanup when dev_set_name() fails within the zcdn_create() function. System administrators should prioritize updating their Linux kernel installations to versions containing the fix, particularly in production environments running IBM mainframe systems with cryptographic workloads. The patch implementation requires modifying the error handling path in the zcrypt driver to ensure that all allocated memory is freed when device name assignment fails, preventing the accumulation of leaked memory resources. Organizations should monitor their cryptographic infrastructure for signs of memory exhaustion and implement proactive monitoring for resource usage patterns that might indicate this vulnerability's exploitation. Additionally, system administrators should consider implementing memory monitoring tools to track resource utilization over time and establish alerting mechanisms for unusual memory consumption patterns. The fix addresses the underlying CWE-401 issue through proper resource management practices that align with kernel security best practices and defensive programming principles, ensuring that all allocated resources are properly released regardless of error conditions. Regular kernel updates and security patch management programs should include verification of s390/zcrypt subsystem integrity to prevent similar memory leak vulnerabilities from persisting in production environments.