CVE-2025-71204: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-71204 is a reference count leak vulnerability in the Linux kernel's SMB server (ksmbd) component, specifically within the parse_durable_handle_context() function. When a command is processed as a replay operation and returns -ENOEXEC, the reference count of the associated ksmbd_file object is not properly released, leading to a resource leak. The vulnerability was published on February 14, 2026, and affects Linux kernel versions 6.6.32 through 6.6.124, 6.9 through 6.12.70, 6.13 through 6.18.10, and 6.19-rc1/rc2/rc3. It carries a CVSS v3.1 base score of 5.5 (Medium) (Feedly).

The root cause is a missing reference count decrement (CWE-911: Improper Update of Reference Count) in the parse_durable_handle_context() function of the kernel's SMB server implementation (smb/server). When the function identifies a replay operation and returns the -ENOEXEC error code, it exits without calling the appropriate release function on the ksmbd_file object, causing its reference count to remain elevated. This is a local vulnerability requiring low privileges and no user interaction, exploitable by a local user who can trigger SMB replay operations against the ksmbd server. Patches addressing this issue have been committed to the stable kernel trees (Kernel Patches).

Successful exploitation of this vulnerability results in a kernel resource leak, which over time can exhaust available file object references and degrade or deny SMB server availability. The primary impact is on availability (rated High in CVSS), with no direct confidentiality or integrity impact. Repeated triggering of the condition could cause the ksmbd SMB server to become unresponsive or crash, affecting all clients relying on the affected Linux-based SMB file server (Feedly).

The Linux kernel maintainers have released patches for all affected stable branches. Users should update to kernel versions 6.6.124 or later, 6.12.70 or later, 6.18.10 or later, or any release beyond 6.19-rc3. Patches are available in the stable kernel tree at the following commits: 07df5ff4, 3296c301, 70dd3513, and 8a15107c. Debian has also issued an updated kernel package (DSA-6141-1) addressing this and related issues. As a workaround, disabling the ksmbd module if SMB server functionality is not required will eliminate exposure (Feedly, Linux Security).

Debian issued a security advisory (DSA-6141-1) covering this vulnerability as part of a broader Linux kernel update, and the fix was noted in Linux compatibility and security news outlets. No significant independent researcher commentary or social media discussion has been identified for this vulnerability (Linux Security, Linux Compatible).