CVE intelligence

CVE-2026-64380

Vulnerability intelligence

Published Jul 25, 2026Sources checked Sep 12, 2026

8.2HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-64380 and is rated High severity with a CVSS score of 8.2. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.4%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-64380?

In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.