CVE-2026-64336

/// Technical description

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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References