Bug 2536618 (CVE-2026-93118)

Summary:	CVE-2026-93118 kernel: usb: gadget: aspeed_udc: check endpoint DMA allocation
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 USB gadget driver for Aspeed UDC. During the device initialization process, a failure to allocate a Direct Memory Access (DMA) buffer is not properly handled. This can lead to the driver attempting to use an invalid memory address, potentially causing a system crash or instability. A local attacker could exploit this to trigger a Denial of Service (DoS).	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 18:53:12 UTC

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

usb: gadget: aspeed_udc: check endpoint DMA allocation

ast_udc_probe() allocates a coherent DMA buffer used as the backing store
for endpoint buffers. ast_udc_init_ep() derives per-endpoint buffer
pointers from udc->ep0_buf, so a failed allocation is dereferenced during
probe.

Check the allocation before endpoint setup. The existing probe error path
called ast_udc_remove(), which unregisters the gadget unconditionally and
is not safe before usb_add_gadget_udc() succeeds. Add a local cleanup
helper for probe failures so pre-registration failures only unwind the
resources that were actually initialized.

This was found by a local static analysis checker for unchecked allocator
returns while scanning Linux 6.16. The change was checked by applying it
to current mainline and by running checkpatch. I do not have access to
Aspeed UDC hardware, so no runtime testing was performed.

Comment 1 gkamathe 2026-09-19 17:02:06 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93118.mbox