Bug 2536788 (CVE-2026-90321)

Summary:	CVE-2026-90321 kernel: ocfs2: validate inline xattrs during inode block validation
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 OCFS2 (Oracle Cluster File System 2) component. Improper validation of inline extended attributes (xattrs) during inode block validation can lead to a use-after-free vulnerability. A local attacker could exploit this by providing specially crafted file system metadata, potentially causing a denial of service or information disclosure.	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 19:33:13 UTC

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

ocfs2: validate inline xattrs during inode block validation

Patch series "ocfs2: validate xattr entry bounds", v7.

This series validates OCFS2 xattr entry name/value bounds when xattr
metadata is read and validated, before getxattr() or listxattr() can walk
out-of-range entry arrays or offsets from corrupted metadata.


This patch (of 2):

ocfs2_validate_inode_block() verifies a dinode before OCFS2 users walk
metadata from it, but inline xattr metadata is still checked only in
operation-specific consumers.  The existing ibody lookup helper validates
inline header placement and entry count, but inode block validation does
not reject entry name/value bounds.

Add a flat xattr entry validator and call it from inode block validation
for inline xattrs.  Keep the operation paths on their existing
header/count lookup checks; the full entry bounds check now runs when the
inode block is validated at read time.

Reject corrupted inline xattr metadata before ocfs2_xattr_ibody_get() or
listxattr() can walk past the inline storage.

Validation reproduced this kernel report:
BUG: KASAN: use-after-free in ocfs2_xattr_find_entry+0x5a/0x170
Read of size 2 at addr ffff8881242a2000 by task python3/529
Call Trace:
  dump_stack_lvl+0x66/0xa0
  print_report+0xce/0x630
  kasan_report+0xe0/0x110
  ocfs2_xattr_find_entry+0x5a/0x170
  ocfs2_xattr_get_nolock+0x20a/0x820
  ocfs2_xattr_get+0x10c/0x1e0
  __vfs_getxattr+0xe2/0x130
  vfs_getxattr+0x185/0x1b0

Comment 1 gkamathe 2026-09-23 08:41:08 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90321.mbox