Bug 2536684 (CVE-2026-90204)

Summary:	CVE-2026-90204 kernel: ocfs2: validate DIO orphan slot during inode read
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 OCFS2 (Oracle Cluster File System 2) component. A local attacker could exploit a vulnerability where a corrupted filesystem metadata entry, specifically an append-DIO dinode, contains an out-of-range orphan slot value. The OCFS2 dinode validator fails to properly check this value, leading to a use-after-free error. This memory corruption can result in system instability or a denial of service.	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 19:05:16 UTC

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

ocfs2: validate DIO orphan slot during inode read

[BUG]
A corrupted append-DIO dinode (high byte at offset 0xa1
corrupted from 0 to 1) can carry an i_dio_orphaned_slot
outside the mounted filesystem slot range and trigger a
use-after-free error:

BUG: KASAN: slab-use-after-free in ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102
Read of size 8 at addr ffff88800b767c00 by task kworker/u8:3/85
Call Trace:
 ...
 ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102
 ocfs2_wipe_inode+0x292/0xf70 fs/ocfs2/inode.c:840
 ocfs2_delete_inode fs/ocfs2/inode.c:1155 [inline]
 ocfs2_evict_inode+0x6c9/0x1170 fs/ocfs2/inode.c:1295
 evict+0x38e/0x8f0 fs/inode.c:810
 iput_final fs/inode.c:1914 [inline]
 iput fs/inode.c:1966 [inline]
 iput+0x55b/0x8b0 fs/inode.c:1926
 ocfs2_recover_orphans+0x610/0xe40 fs/ocfs2/journal.c:2374
 ocfs2_complete_recovery+0x5af/0xd00 fs/ocfs2/journal.c:1373
 ...

[CAUSE]
ocfs2_del_inode_from_orphan() uses i_dio_orphaned_slot to index the
slot-local system inode cache. The dinode validator does not check
this active slot, so an out-of-range value produces an invalid cache
entry pointer that is dereferenced as an inode pointer.

[FIX]
Reject an active i_dio_orphaned_slot outside the slot range during
dinode validation, before DIO orphan recovery can consume it.

Comment 1 Mauro Matteo Cascella 2026-09-24 10:52:38 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90204.mbox