Bug 2559690 (CVE-2026-99087)

Summary:	CVE-2026-99087 kernel: dm-integrity: fix NULL pointer dereference when the 'R' flag is used
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 device-mapper integrity (dm-integrity) subsystem. A local user with administrative privileges can cause a Denial of Service (DoS) by activating a storage device in read-only mode when dirty journal bitmap flags are set. This issue occurs because the driver attempts to perform write operations and read journal data on a read-only device during resume, triggering a NULL pointer dereference and crashing the system.	Story Points:	---
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Last Closed:		Type:	---
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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 13:13:58 UTC

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

dm-integrity: fix NULL pointer dereference when the 'R' flag is used

If the dm-integrity device has the SB_FLAG_DIRTY_BITMAP flag set and the
user activates the device in the 'R' mode, a crash in dm_integrity_resume
happens because the function attempts to read the journal containing the
bitmap.

This patch makes dm-integrity skip any writes to the device in
dm_integrity_resume if the device is activated in the 'R' mode.

Comment 1 gkamathe 2026-10-26 18:08:07 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99087.mbox