Bug 2540565 (CVE-2026-93816)

Summary:	CVE-2026-93816 kernel: f2fs: validate inline dentry name lengths before conversion
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 Flash-Friendly File System (F2FS). When converting inline directory entries into standard directory blocks, the kernel does not properly validate recorded filename lengths before copying them. A local user could exploit this flaw by mounting a specially crafted or corrupted file system image to trigger an out-of-bounds memory read. This could result in a system crash leading to a Denial of Service (DoS) or potential unauthorized 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 2026-09-24 17:17:36 UTC

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

f2fs: validate inline dentry name lengths before conversion

Inline dentry conversion copies names out of the inline dentry area
before checking that each recorded name length fits in the available
filename slots.

A corrupted image can therefore make the conversion path read past
the inline filename storage while building the regular dentry block.

Validate each inline dentry name length against the inline filename
area before copying it.

Comment 1 Mauro Matteo Cascella 2026-09-28 14:02:22 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93816.mbox