Bug 2532050 (CVE-2026-89458)

Summary:	CVE-2026-89458 kernel: s390/dasd: Do not complete a failed ESE read as successful
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:	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 s390/dasd component. The `dasd_int_handler()` function incorrectly marks failed Extended Sense Data (ESE) read operations as successful when processing unallocated ESE tracks. This leads to the block layer receiving stale or uninitialized memory instead of properly zeroed memory. A local attacker could exploit this vulnerability to potentially gain access to sensitive information, resulting in information disclosure.	Story Points:	---
Clone Of:		Environment:
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 20:18:49 UTC

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

s390/dasd: Do not complete a failed ESE read as successful

dasd_int_handler() completes an NRF read of an unallocated ESE track by
calling ese_read() and unconditionally marking the request
DASD_CQR_SUCCESS. dasd_eckd_ese_read() can return an error before it has
zeroed the destination buffer: a failed sense-data parse or a current
track outside the requested range both return early, leaving the
destination pages untouched. The request is still completed successfully,
so the block layer is handed stale / uninitialized memory instead of
zeros.

Check the ese_read() return value and fail the request through the normal
error path instead of forcing DASD_CQR_SUCCESS.

Comment 1 Mauro Matteo Cascella 2026-09-14 16:37:07 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89458.mbox