CVE-2023-32253 in Linux
Summary
by MITRE • 08/03/2025
A flaw was found in the Linux kernel's ksmbd component. A deadlock is triggered by sending multiple concurrent session setup requests, possibly leading to a denial of service.
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Analysis
by VulDB Data Team • 08/05/2025
The vulnerability identified as CVE-2023-32253 resides within the Linux kernel's ksmbd component, which serves as an SMB/CIFS server implementation designed to provide file sharing capabilities over network protocols. This flaw manifests as a deadlock condition that occurs when multiple concurrent session setup requests are processed simultaneously, creating a scenario where system resources become permanently blocked and unavailable for legitimate operations.
The technical root cause of this vulnerability stems from improper synchronization mechanisms within the ksmbd subsystem's session management code. When multiple clients attempt to establish SMB sessions concurrently, the component fails to properly handle the race conditions that arise during session setup operations. This improper handling leads to threads becoming indefinitely blocked while waiting for locks or resources that are never released, effectively creating a deadlock state that prevents further session establishment or processing of legitimate requests.
From an operational perspective, this vulnerability presents a significant denial of service risk to systems running ksmbd servers, particularly in environments where multiple clients or applications might simultaneously attempt to connect to shared resources. The impact extends beyond simple service interruption as the deadlock condition can persist until the system is manually restarted, potentially affecting business continuity and availability of critical file sharing services. Network administrators and system operators face the challenge of identifying and mitigating this issue without disrupting legitimate user access to shared resources.
The vulnerability aligns with CWE-362, which describes a race condition error that occurs when multiple threads or processes access shared resources without proper synchronization, leading to unpredictable behavior and system instability. Additionally, this flaw can be categorized under ATT&CK technique T1499.004, which involves network denial of service attacks through resource exhaustion or locking mechanisms that prevent legitimate access to network services.
Mitigation strategies should prioritize applying the latest kernel updates that contain patches addressing the synchronization issues within the ksmbd component. System administrators should also implement monitoring solutions to detect unusual patterns of concurrent session requests that might indicate exploitation attempts. Network segmentation and rate limiting mechanisms can help reduce the impact of potential attacks by limiting the number of concurrent connection attempts from individual clients or networks. Organizations should also consider implementing redundant SMB services or alternative file sharing solutions as part of their disaster recovery planning to ensure continued availability during remediation efforts.