Bug 2521494 (CVE-2026-74690)

Summary:	CVE-2026-74690 kernel: s390/ism: Fix UAF of sba and ieq during ism_dev_exit()
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
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Doc Text:	A flaw was found in the Linux kernel's s390/ism component. An interrupt handler could concurrently access data structures (sba and ieq) that have already been freed during the ism_dev_exit() process. This Use-After-Free (UAF) vulnerability could lead to system instability or potentially allow for privilege escalation.	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 15:48:17 UTC

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

s390/ism: Fix UAF of sba and ieq during ism_dev_exit()

A ism interrupt handler can be active in parallel with ism_dev_exit(),
accessing freed data structures.

No new interrupts will be generated after unregister_ieq(). Drain ongoing
interrupt handlers by free_irq(), before freeing ism data structures.

Comment 1 gkamathe 2026-08-24 12:49:28 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082233-CVE-2026-74690-0118@gregkh/T