Description
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: composite: fix dead empty check in the USB_DT_OTG handler
The OTG branch of composite_setup() falls back to the first
configuration when none is selected:
if (cdev->config)
config = cdev->config;
else
config = list_first_entry(&cdev->configs,
struct usb_configuration, list);
if (!config)
goto done;
...
memcpy(req->buf, config->descriptors[0], value);
list_first_entry() never returns NULL. On an empty list it returns
container_of() of the list head. So the "if (!config)" check is dead.
When cdev->configs is empty, config points at the head inside struct
usb_composite_dev. config->descriptors[0] reads whatever sits at that
offset. The memcpy copies up to w_length bytes of it into the response
buffer.
cdev->configs can be empty in two cases. One is a teardown race on
gadget unbind with a control transfer in flight. The other is a driver
that sets is_otg before it adds a config. A reproducer that holds
cdev->configs empty triggers a KASAN fault in this branch.
Use list_first_entry_or_null() so the existing check does its job.
usb: gadget: composite: fix dead empty check in the USB_DT_OTG handler
The OTG branch of composite_setup() falls back to the first
configuration when none is selected:
if (cdev->config)
config = cdev->config;
else
config = list_first_entry(&cdev->configs,
struct usb_configuration, list);
if (!config)
goto done;
...
memcpy(req->buf, config->descriptors[0], value);
list_first_entry() never returns NULL. On an empty list it returns
container_of() of the list head. So the "if (!config)" check is dead.
When cdev->configs is empty, config points at the head inside struct
usb_composite_dev. config->descriptors[0] reads whatever sits at that
offset. The memcpy copies up to w_length bytes of it into the response
buffer.
cdev->configs can be empty in two cases. One is a teardown race on
gadget unbind with a control transfer in flight. The other is a driver
that sets is_otg before it adds a config. A reproducer that holds
cdev->configs empty triggers a KASAN fault in this branch.
Use list_first_entry_or_null() so the existing check does its job.
Published:
2026-07-25
Score:
n/a
EPSS:
< 1% Very Low
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
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References
History
Sat, 25 Jul 2026 09:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: usb: gadget: composite: fix dead empty check in the USB_DT_OTG handler The OTG branch of composite_setup() falls back to the first configuration when none is selected: if (cdev->config) config = cdev->config; else config = list_first_entry(&cdev->configs, struct usb_configuration, list); if (!config) goto done; ... memcpy(req->buf, config->descriptors[0], value); list_first_entry() never returns NULL. On an empty list it returns container_of() of the list head. So the "if (!config)" check is dead. When cdev->configs is empty, config points at the head inside struct usb_composite_dev. config->descriptors[0] reads whatever sits at that offset. The memcpy copies up to w_length bytes of it into the response buffer. cdev->configs can be empty in two cases. One is a teardown race on gadget unbind with a control transfer in flight. The other is a driver that sets is_otg before it adds a config. A reproducer that holds cdev->configs empty triggers a KASAN fault in this branch. Use list_first_entry_or_null() so the existing check does its job. | |
| Title | usb: gadget: composite: fix dead empty check in the USB_DT_OTG handler | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-07-25T08:50:08.338Z
Reserved: 2026-07-19T15:36:31.782Z
Link: CVE-2026-64347
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.