Bug 2532158 (CVE-2026-89719)

Summary:	CVE-2026-89719 kernel: zram: fix out-of-bounds access in read_block_state()
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 zram module. This vulnerability occurs when the `read_block_state()` function calculates the number of pages before acquiring a device lock. If the zram device is reset and reinitialized with a smaller disk size, the function can attempt to access memory beyond the bounds of the newly allocated table. This out-of-bounds access can lead to system instability or a denial of service (DoS).	Story Points:	---
Clone Of:		Environment:
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 2026-09-11 21:01:34 UTC

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

zram: fix out-of-bounds access in read_block_state()

read_block_state() calculates nr_pages before taking dev_lock.  If the
device is reset and reinitialized with a smaller disksize before lock
acquisition, nr_pages still describes the old table.  The subsequent loop
can then call slot_lock() past the end of the newly allocated table.

Read disksize after acquiring dev_lock and checking that the device is
initialized.  The read lock then keeps the table and its bound stable for
the duration of the scan.

Comment 1 Keith Grant 2026-09-21 14:56:07 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89719.mbox