A vulnerability in the Linux kernel SMB client allows for improper mode masking, which could lead to service disruption or integrity issues.

The vulnerability exists within the SMB client implementation where the parse_dacl function fails to properly mask server-provided mode values to 07777. This missing validation allows an attacker to influence file mode bits during operation, which can be leveraged to cause an availability impact or unauthorized integrity modifications.

The flaw carries a CVSS score of 7.1, indicating a high potential for impact within enterprise environments relying on SMB for file sharing. Successful exploitation can lead to a denial of service (system crash or hang) or the ability to manipulate file permissions in ways that bypass standard security policies, potentially leading to data compromise or unauthorized access to sensitive files.

Immediate Action: Update your Linux kernel to version 5.10.261, 5.15.212, 6.1.178, 6.6.145, or newer, as provided by your distribution vendor.

Proactive Monitoring: Monitor system logs for unusual kernel warnings or SMB client errors that may indicate exploitation attempts.

Compensating Controls: Restrict access to SMB shares to trusted clients only and implement network segmentation to minimize the exposure of the kernel SMB client to potentially malicious servers.

Public Exploit Available: No

Given the high severity of this kernel-level vulnerability, organizations should prioritize patching their Linux infrastructure. Administrators must verify their kernel versions against the fixed releases and apply the necessary updates to prevent potential service disruption or integrity compromise caused by malformed SMB responses.