Bug 2521486 (CVE-2026-74652)

Summary:	CVE-2026-74652 kernel: serial: amba-pl011: cancel RS485 hrtimers after freeing IRQ
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 amba-pl011 serial driver. The RS485 trigger high-resolution timers (hrtimers) can fire after the device management (devm)-managed port is freed. This occurs because the timers are not properly canceled before the interrupt request (IRQ) is freed, allowing a use-after-free condition. A local attacker could potentially exploit this to cause a denial of service.	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 2026-08-22 15:47:55 UTC

In the Linux kernel, the following vulnerability has been resolved:

serial: amba-pl011: cancel RS485 hrtimers after freeing IRQ

The RS485 trigger hrtimers are embedded in the devm-managed port and can
fire after it is freed. The IRQ handler can arm a timer, so free the IRQ
first and then cancel both timers.

Complete the RS485 stop without arming a timer, and cancel the timers
in remove() for the suspend-then-unbind path, where shutdown is not
called.

This issue was found by an in-house static analysis tool.

Comment 1 gkamathe 2026-08-24 11:56:52 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082226-CVE-2026-74652-3d26@gregkh/T