The Linux kernel's SMB client function cifs_sanitize_prepath contains a vulnerability causing an out-of-bounds read when called with empty or delimiter-only strings. The function attempts to access memory before the current cursor position without proper boundary checks. The patch introduces an early exit after stripping delimiters to prevent this invalid memory access. This vulnerability is tracked as CVE-2026-43112 and was discovered via manual code audit and verified with a standalone test case using AddressSanitizer, which triggered a segmentation fault on affected inputs. Red Hat has issued security advisories and kernel updates for Red Hat Enterprise Linux 10 to remediate this issue.

The vulnerability allows an out-of-bounds read in kernel memory, which can lead to system crashes (segmentation faults) and potentially escalate to higher impact outcomes such as confidentiality, integrity, and availability compromises as indicated by the CVSS vector. The issue affects the Linux kernel SMB client code and could impact systems running vulnerable kernel versions. No known exploits in the wild have been reported at this time.

Red Hat has released an official security update for Red Hat Enterprise Linux 10 that fixes this vulnerability. Users should apply the kernel update provided in RHSA-2026:34911 and reboot their systems to ensure the patch takes effect. Since this is a kernel-level fix, applying the vendor's update is the recommended and effective mitigation. Patch status is confirmed by the vendor advisory.