Bug 2507055 (CVE-2026-64336)

Summary:	CVE-2026-64336 kernel: USB: serial: keyspan_pda: fix information leak
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's keyspan_pda USB serial driver. An issue with the write() callback function allows it to report more data written than was actually provided. This can lead to the system writing data beyond its allocated buffer, resulting in an information leak. A local attacker could exploit this to potentially gain access to sensitive information.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-25 10:02:40 UTC

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.

Comment 1 Mauro Matteo Cascella 2026-07-29 18:31:41 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072515-CVE-2026-64336-82b2@gregkh/T