Bug 2536174 (CVE-2026-90262)

Summary:	CVE-2026-90262 kernel: btrfs: retry verity reads for not-uptodate Merkle folios
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 btrfs filesystem. This flaw occurs when the `btrfs_read_merkle_tree_page()` function encounters a Merkle folio that is not up-to-date. Instead of retrying the read, the system incorrectly treats this as a permanent error, causing transient read failures to become persistent. This can lead to a denial of service (DoS) for read operations, preventing legitimate access to data on affected btrfs volumes.	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 16:41:31 UTC

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

btrfs: retry verity reads for not-uptodate Merkle folios

btrfs_read_merkle_tree_page() can find a folio in the mapping that is not
uptodate.  After taking the folio lock, the current code treats that state
as a read error and returns -EIO.

That can make a previous transient read failure sticky.  If the failed read
left a not-uptodate folio in the mapping, later callers find that folio and
fail instead of retrying the read.

Keep the existing page-cache insertion and locking order, but retry the
Merkle item read when a not-uptodate folio is found in the mapping.  Also
unlock the folio when read_key_bytes() fails so that a later caller can
lock it and retry the read.

Comment 1 gkamathe 2026-09-23 21:51:03 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90262.mbox