Bug 2513394 (CVE-2026-68400)

Summary:	CVE-2026-68400 kernel: firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation
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:	rhel-process-autobot, 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 arm_ffa firmware component. An incorrect calculation of the Endpoint Memory Access Descriptor offset could lead to improper memory access. This issue arises from defaulting to a fixed size instead of using the descriptor's specified offset, potentially causing out-of-bounds memory operations.	Story Points:	---
Clone Of:		Environment:
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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 2026-08-10 12:34:56 UTC

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

firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation

Use the descriptor's `ep_mem_offset` to calculate the start of the endpoint
memory access array and to comply with the FF-A spec instead of defaulting
to `sizeof(struct ffa_mem_region)`.
This requires moving `ffa_mem_region_additional_setup()` earlier in the setup
flow.
Also, add sanity checks to ensure the calculated descriptor offsets do not
exceed `max_fragsize`.

Comment 1 Mauro Matteo Cascella 2026-08-11 21:10:26 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081048-CVE-2026-68400-60b8@gregkh/T