The Linux kernel's SMB client contains a flaw in the function that translates POSIX attributes to Windows ACLs. When a malicious SMB server sends a malformed POSIX directory entry, the parsing routine fails but the code continues to use the uninitialized fields for the owner and group. These garbage values are converted to a SID string and sent to the userspace idmap daemon, exposing kernel stack contents to unprivileged processes.

The vulnerability affects the Linux kernel, specifically the SMB client module. No specific kernel version range is listed, so any kernel build that includes the unpatched SMB client is potentially impacted.

The flaw is a classic instance of uninitialized memory use that can be exploited if an attacker controls or can influence the SMB server's response. While no EPSS score is available, the potential for kernel data leakage is sufficient for concern. The CVE is not listed in the CISA KEV catalog, but the impact remains a significant information disclosure risk. An attacker who can establish SMB traffic with the vulnerable client could trigger the flaw and export arbitrary kernel memory to userspace, compromising system confidentiality.