Bug 2536140 (CVE-2026-90434)

Summary:	CVE-2026-90434 kernel: isofs: release zisofs block pointer buffer head
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 `isofs` filesystem driver. When processing compressed block pointer tables via the `zisofs_fill_pages()` function, a memory resource is not properly released upon successful operation. A local attacker could potentially exploit this resource mismanagement, possibly by mounting a specially crafted ISO image, leading to resource exhaustion and a denial of service (DoS) on the system.	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 16:39:42 UTC

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

isofs: release zisofs block pointer buffer head

zisofs_fill_pages() reads the compressed block pointer table.  The error
paths release the current buffer_head, the loop also releases the old
buffer_head when it advances. However, the success path leaves the last
buffer_head referenced. Release it before returning success.

Comment 1 gkamathe 2026-09-20 02:42:02 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90434.mbox