CVE-2026-64336 and is rated Medium severity with a CVSS score of 5.5. 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
EPSS0.1%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-64336?
In the Linux kernel, the following vulnerability has been resolved:
USB: serial: keyspan_pda: fix information leak
The write() callback is supposed to return the number of characters accepted or a negative errno. Since the addition of write fifo support the keyspan_pda implementation will however return the number characters submitted to the device if the write urb is not already in use.
If this number is larger than the number of characters passed to write(), the line discipline continues writing data from beyond the tty write buffer.
Fix the information leak by making sure that keyspan_pda_write_start() returns zero on success as intended.