Evidence-led vulnerability intelligence · 2026-07-25 15:47 IST

CVE-2026-64347

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.

MEDIUM · 5.5Linux

Executive briefing

The source record describes: 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. The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.

Assessment: Potential exposure only — validate the installed product, exact version, configuration and vendor applicability before treating an asset as confirmed vulnerable.

Evidence confidence: Moderate Evidence-derived, not an exploitability verdict

Severity & attack characteristics

5.5 / 10 · 3.1

CVSS vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack vectorL
Attack complexityL
Privileges requiredL
User interactionN
ScopeU
Confidentiality impactN
Integrity impactN
Availability impactH

Technical explanation & impact

The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.

Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.

Weakness classification

CWE-667

Affected products and versions

Products below are parsed from NVD vulnerable CPE configuration entries. Version boundaries are shown as published; verify applicability with the vendor.

VendorProductVersion evidence
linuxlinux_kernelfrom (inclusive) 6.19; before 7.1.4 · CPE version 7.2 · CPE version 7.2

Remediation & validation

  1. Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
  2. Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
  3. Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
  4. Validate the remediation with a version check and vulnerability rescan, then retain change evidence.

No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.

Vendor advisories, patches & exploit references

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Threat intelligence, made actionable · CVE data sourced from the NVD