Bug 2559681 (CVE-2026-98935)

Summary:	CVE-2026-98935 kernel: kernel: Information disclosure via uninitialized stack memory in RTC driver
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, 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 Real-Time Clock (RTC) driver. This information disclosure vulnerability occurs because the driver fails to initialize memory padding within an internal data structure before copying alarm details to user space. A local user can exploit this flaw by querying the RTC alarm settings to read uninitialized kernel stack memory, potentially exposing sensitive system data.	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 2026-10-23 13:01:06 UTC

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

rtc: dev: zero-initialize struct rtc_wkalrm to prevent information leak

The struct rtc_wkalrm has padding holes after the 'pending' member.
When returned to userspace via the RTC_WKALRM_RD ioctl, uninitialized
kernel stack data residing in these holes may be leaked.

Zero-initialize the struct at declaration to eliminate this information
leak risk.

Fixes smatch warnings:
- drivers/rtc/dev.c:392 rtc_dev_ioctl() warn: check that 'alarm' doesn't
  leak information (struct has a hole after 'pending')