Bug 2507066 (CVE-2026-64256)

Summary:	CVE-2026-64256 kernel: xfs: don't wrap around quota ids in dqiterate
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:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in the Linux kernel's XFS filesystem. This vulnerability occurs in the `dqiterate` function, where an unsigned 32-bit quota identifier (`q_id`) can wrap around to zero if it reaches its maximum value. This integer overflow can cause the iteration of quota IDs to restart, potentially leading to a denial of service (DoS) by preventing proper processing of filesystem quotas.	Story Points:	---
Clone Of:		Environment:
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Regression:	---	Mount Type:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-25 10:03:14 UTC

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

xfs: don't wrap around quota ids in dqiterate

LOLLM noticed that q_id is an unsigned 32-bit variable.  If it happens
to be set to XFS_DQ_ID_MAX due to a filesystem that actually has a dquot
for ID_MAX, then this addition will truncate to zero and the iteration
starts over.  Fix this by casting to u64.

Comment 1 Mauro Matteo Cascella 2026-07-30 10:07:02 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072553-CVE-2026-64256-643b@gregkh/T