Bug 2536538 (CVE-2026-90197)

Summary:	CVE-2026-90197 kernel: HID: haptic: don't write an uninitialized value to unhandled usages
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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 Human Interface Device (HID) haptic subsystem. A local attacker could exploit a vulnerability in the `fill_effect_buf()` function, which incorrectly writes uninitialized or leftover memory values to the `field->value[]` array for unhandled haptic usages. This uninitialized data is subsequently serialized into the effect's report buffer by `hid_output_report()`. This vulnerability could lead to information disclosure, potentially exposing sensitive kernel memory contents.	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 2026-09-17 18:20:20 UTC

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

HID: haptic: don't write an uninitialized value to unhandled usages

fill_effect_buf() initializes value only for the four haptic usages
handled by its switch, but writes it to field->value[] for every usage.
An unhandled usage can therefore receive either an uninitialized value
or one left over from the previous usage. hid_output_report() then
serializes that value into the effect's report buffer.

Skip unhandled usages instead. This also matches switch_mode(), which
only updates fields it recognizes.

Found with Clang's -Wconditional-uninitialized.

Comment 1 Keith Grant 2026-09-23 22:28:08 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90197.mbox