CVE-2026-31433

VULNERABILITY OVERVIEW CVE-2026-31433 is an out-of-bounds (OOB) write vulnerability in the Linux kernel's ksmbd (SMB server implementation) that affects the get_file_all_info() function when processing compound SMB requests. The flaw occurs when a QUERY_DIRECTORY request is combined with a QUERY_INFO (FILE_ALL_INFORMATION) request, and insufficient buffer validation allows the filename to be written beyond allocated memory boundaries during UTF-16 conversion. SEVERITY ASSESSMENT The vulnerability requires a local or network-based attacker to craft a malicious compound SMB request, though the attack complexity appears moderate given the specific conditions needed (compound request structure and buffer consumption patterns). The potential impact includes memory corruption, information disclosure, and possible privilege escalation or denial of service, depending on the kernel memory layout and protection mechanisms present on the affected system. While CVSS scoring is unavailable, the FAUCET Risk Score of 20.0/100 and EPSS score of 0.00013 suggest relatively low overall risk in the current threat landscape. EXPLOITATION STATUS There is no evidence of active exploitation, no publicly available exploit code, and the vulnerability is not included on the CISA Known Exploited Vulnerabilities (KEV) catalog. Community attention appears minimal, with this issue appearing to be addressed through standard Linux kernel patching processes. Organizations should apply available kernel updates containing the fix when the vulnerability details become more widely documented.